A growing number of espionage cases are rattling Taiwan’s ruling Democratic Progressive Party (DPP), piercing deep into the island’s political and military core and exposing worrying vulnerabilities in its counter-intelligence systems.
The mounting revelations of infiltration – from top government officials’ close aides to active-duty military personnel – have sparked alarm over Beijing’s intensifying efforts to undermine Taiwan authorities from within, raising questions of public trust in the administration of William Lai Ching-te.
At least five people closely associated with senior DPP politicians are under investigation or have been detained for allegedly leaking classified information to mainland Chinese intelligence. Among them are aides to Taiwanese leader Lai and National Security Council secretary general Joseph Wu.
The high-level breaches have fuelled fears that Beijing’s decades-long efforts to cultivate spy networks in Taiwan are reaching new levels.
“The frequent surfacing of Chinese spy cases in Taiwan suggests that China’s espionage network here is watertight – they have developed a highly effective system to lure certain Taiwanese people to do the job,” said Huang Huei-hua, director of the Taiwan Global Talk think tank.
“Even top officials are now surrounded by suspected spies. It’s a sign that the DPP government has loosened its counter-intelligence screws.”
Beijing views Taiwan as part of China to be reunited, by force if necessary. Since Lai, of the DPP, took office as the island’s leader in May, tensions across the Taiwan Strait have worsened.
While most countries, including the United States, do not recognise Taiwan as an independent state, Washington opposes unilateral changes to the cross-strait status quo by force and is committed to supplying arms for the island’s defence.
According to Taiwan’s National Security Bureau, 159 people have been indicted for spying for mainland China since 2020. Nearly 60 per cent – or 95 individuals – were either active-duty or retired military personnel. In 2024 alone, 64 people were charged, a marked increase from 48 the previous year. Among them were 28 active-duty officers and 15 retirees.
A bureau report last week said mainland Chinese agents often worked through criminal syndicates, religious groups, temples and civilian organisations to recruit retired military personnel. They, in turn, helped to lure serving members – especially those in financial distress – by offering loans, or cash through online transfers or underground banks.
The report showed that since 2020, Beijing had infiltrated every level of Taiwan’s military: 46 of those charged were commissioned officers; 27 were non-commissioned officers; and 22 were rank-and-file soldiers.
In one of the cases most alarming to Taipei this year, three military police officers responsible for guarding Lai, as well as an army soldier in the military’s intelligence unit, were sentenced last month to between five years, 10 months and seven years in prison for passing classified material to Beijing.
A separate group of seven officers – including guards from the Shihlin Military Police Squad in Taipei and naval missile boat units – were convicted in February of leaking patrol routes and ammunition depot locations in exchange for funds.
Five of the officers had filmed themselves waving the flag of mainland China and pledging not to resist in the event of an attack from the People’s Liberation Army.
The scandal deepened when prosecutors last week detained Ho Jen-chieh, a long-time aide to Joseph Wu, who served as foreign minister from 2018 until May last year. Ho is suspected of leaking sensitive diplomatic intelligence while serving under Wu.
Wu’s office confirmed that Ho had stepped down in March last year, two months before Wu became the island’s top national security official. Wu’s team vowed full cooperation with the investigation and support for “severe sanctions against any individual involved in infiltration or ‘united front’ activities”.
The DPP swiftly expelled Ho. “His alleged actions have severely damaged the party’s reputation,” the DPP’s Yilan county committee said. “Espionage is utterly incompatible with the party’s core values.”
Ho’s arrest follows a string of similar cases, which involve Wu Shang-yu, an adviser to Lai; Chiu Shih-yuan, former deputy head of the Taiwan Institute of Democracy; and Huang Chu-jung, an aide to DPP New Taipei councillor Lee Yu-tien. All are suspected of being part of the same network, allegedly recruited years ago by mainland agents and later given the task of expanding their circle. All three have since been expelled from the party.
Sheng Chu-ying, a former aide to several DPP lawmakers, including former legislative speaker Yu Shyi-kun, was recently released on bail while prosecutors investigate his suspected links to Beijing.
The opposition coalition of the mainland-friendly Kuomintang (KMT) and the smaller Taiwan People’s Party (TPP) has seized on the scandals to criticise the DPP’s security record. “Colluding with the Chinese Communists and betraying Taiwan is a severe matter,” KMT chairman Eric Chu Li-luan said. “The DPP must root out spies within its ranks, regardless of political affiliation.”
KMT spokeswoman Yang Chih-yu pointed to the widespread scope of the cases. “It’s not just the legislature – even the presidential office, foreign ministry and National Security Council have been compromised,” she said. “Who’s the real betrayer of Taiwan?”
TPP chairman Huang Kuo-chang echoed the criticism, branding the DPP “a national team of Chinese spies”. He demanded that Lai investigate the full extent of the infiltration and questioned why Joseph Wu had not been dismissed despite his aide’s alleged role in the scandal.
Ho’s close relationship with Wu – reportedly spanning nearly a decade – has added to the public outcry.
“This raises questions about how much classified information may have been leaked and whether the DPP’s internal vetting system is broken,” Huang said.
Ho served closely alongside Wu, starting as his aide when Wu was DPP secretary general from 2014 to 2016, then following him through senior posts at the National Security Council and the island’s presidential office before joining him again at the foreign ministry.
In response, the DPP has pledged a full audit of all aides and personnel with long-term access to classified information.
At a party meeting on Wednesday, Lai ordered DPP officials to provide advance notice of any planned trips to mainland China, Hong Kong or Macau – and to submit reports afterwards. He also called for regular security training for DPP staff.
Taiwanese Defence Minister Wellington Koo Li-hsiung said the military would strengthen security screenings and bar 62 active-duty officers with mainland Chinese residency permits from gaining access to classified data. The defence ministry also sought to reinstate military courts to handle criminal cases, including espionage activities involving serving personnel.
Still, experts warn that the government’s vetting mechanisms remain flawed.
Su Tzu-yun, director of the Institute for National Defence and Security Research, a military-affiliated think tank, said mainland Chinese operatives had strategically placed assets across various agencies to piece together a broad picture of Taiwan’s security posture.
“There’s a major blind spot in Taiwan’s background check system,” he said. “Security checks are only done when someone takes office – there’s no follow-up mechanism.”
Ying-yu Lin, a professor of international relations and strategic studies at Taiwan’s Tamkang University, noted that even low-level aides could gain access to sensitive data through document handling and communications.
“Moreover, their colleagues or subordinates could eventually rise to more senior roles – expanding Beijing’s reach over time.”
Ho Chih-yung, a professor of general education at Taiwan’s National Tsing Hua University, said the rash of spy cases raised uncomfortable questions about loyalty – and human nature.
“Even if some individuals, like DPP political figures, often claim not to sell out Taiwan, how do they respond when faced with money? These are real tests.”
As Beijing sharpens its non-military grey-zone warfare against Taiwan, the rising tide of espionage “is not just a national security challenge – it’s a political reckoning”, Ho said.
Huang at Taiwan Global Talk noted that mainland Chinese infiltration efforts dated back to the 1950s, during the era of late KMT leader Chiang Kai-shek.
“It would be misguided to link the recent uptick in espionage solely to Lai’s anti-China stance,” she said, adding that while Lai’s policies might give Beijing greater incentive to step up infiltration, “the roots of these networks are much deeper”.
She warned that each uncovered case added fuel to cross-strait tensions. “Taiwan and China are locked in a protracted struggle of political warfare and counter-warfare. Every spy arrest ratchets up the pressure – it’s a vicious cycle that continues to destabilise the region,” she said.
Huang said Beijing had significantly refined its infiltration tactics in recent years, posing a growing challenge to the Lai administration.
“This not only undermines Taiwan’s intelligence capabilities – it also erodes public trust in the authority of Lai’s government,” she said. “It’s a serious and urgent issue.”