A Hong Kong bookseller who fled China in 2016 after being detained for selling banned titles in the mainland said Wednesday his fate could be sealed if Hong Kong reaches an agreement with mainland China to surrender fugitives.

The government's proposal last week to amend laws to facilitate the handover of people wanted in jurisdictions where no extradition agreement with Hong Kong exists, such as Taiwan and China, is bad news for Lam Wing-kee.

"If I stay in Hong Kong, I will most definitely (be extradited to mainland China) under the new arrangement," Lam, 63, told Kyodo News in an interview. "Having been captured in the mainland, knowing the tactics of the authorities, I'm as good as dead if extradited."

(Lam Wing-kee)

One of five Hong Kong booksellers whose disappearances into mainland China in 2015 caused widespread concern about overreach by Chinese law enforcement, Lam jumped bail during a conditional release from nearly eight months of detention.

Of the remaining four, naturalized Swedish publisher Gui Minhai is in custody in mainland China for allegedly "stealing state secrets," two others are barred from leaving the mainland and one is free but under pressure to keep mum, according to Lam.

Recalling the ordeal he has faced since being taken into custody in Shenzhen in October 2015, Lam said thoughts of suicide came up when he was told he could forever lose his freedom.

"(The extradition pact) has a big influence as it covers not only Hong Kong people but Taiwanese, or people from foreign countries, or anyone in Hong Kong. The Chinese government could claim that someone violated the relevant offenses and ask the Hong Kong authorities for extradition," Lam said.

"Political dissidents or advocates for independence in Hong Kong could be extradited to the mainland," he said.

Hong Kong has not signed a deal over fugitive transfer with China or Taiwan, which have differing judicial systems, since the former British colony's return to Chinese rule in 1997.

The government is proposing to amend the law in the wake of a Taiwan murder case in which there is no legal means for Hong Kong to hand over the suspect to Taiwan.

Hong Kong man Chan Tong-kai, then 19, fled Taiwan after allegedly killing his Hong Kong girlfriend Poon Hiu-wing, 20, while the pair were traveling in Taipei in February last year.

After returning to Hong Kong, Chan was arrested for theft after using Poon's stolen bank card to withdraw money from her bank account in both Taiwan and Hong Kong. The Hong Kong government has ignored Taiwan's repeated requests for mutual legal assistance over the case.

Security Secretary John Lee has insisted the amendment, in order to effectively plug legal loopholes, must not only cover Taiwan but all jurisdictions without extradition agreements with Hong Kong.

Critics including pro-democracy lawmakers say the government intends to use the Taiwan murder case as a pretext to facilitate China's extradition requests and thereby stripping protections guaranteed under the Basic Law, the mini-constitution by which Hong Kong's semiautonomous status was stipulated.

Under the amendment, extradition requests will be examined on a case-by-case basis, and Hong Kong's leader would have to issue an "authority to proceed" before a court vets a case in an open hearing.

It would apply to 46 types of crimes including murder, with allegations related to politics, religion and race not considered to be valid reasons for extradition.

Chief Executive Carrie Lam said in the legislature Wednesday that her duty in the extradition arrangement would be "only to initiate the procedure." She did not say if she could or would deny requests for extradition from China.

"I had thought that I could safely stay in Hong Kong after the bookstore incident. How would anyone imagine that the authorities will resort to such extreme measures to stifle free speech?" Lam Wing-kee said.

"(With the extradition pact) China's constitution is literally implemented in Hong Kong, overruling the Basic Law. One cannot live happily in Hong Kong when freedom, like breathing, is constrained."

He said living in Taiwan is an unlikely option and he might seek to move overseas to avoid being probably sent to China once the law is amended.

Apart from Lam, the extradition pact could affect a few others including Hong Kong businessmen Joseph Lau and Steven Lo who were sentenced in absentia to imprisonment by Macau in a corruption trial, and fugitive siblings Thaksin and Yingluck Shinawatra, both former Thai prime ministers, who frequently visit Hong Kong.

Currently, Hong Kong has no extradition agreement with Macau and Thailand.

The amendment bill is expected to be introduced within months.