Taiwan has opened an office to help people fleeing Hong Kong after China imposed new national security laws in the for British colony.

A senior minister said Taiwan hoped to seize the opportunity to attract professionals and capital from the city.

It came as Hong Kong police reported late on Wednesday afternoon (Australian time) they had made their first arrest under the sweeping national security law Beijing introduced less than 24 hours earlier.

It was a man holding a flag advocating independence – pictures posted by police on Twitter showed the flag lying on a footpath in front of a man wearing a black T-shirt with “Free Hong Kong” on it.

Tweet from @hkpoliceforce

The contentious law, which came into effect on Tuesday, will target crimes of secession, subversion, terrorism and collusion with foreign forces with up to life in prison, heralding a more authoritarian era for the Asian financial hub.

The law has been widely condemned in democratic and Chinese-claimed Taiwan. About 200 people have already fled to the island from Hong Kong since pro-democracy protests began in 2019, rights groups say.

Taiwan opened the office in downtown Taipei on the sensitive anniversary of the return of Hong Kong, a former British colony, to Chinese rule in 1997.

It showcased the island’s determination to aid Hong Kongers, said Chen Ming-tong, the head of Taiwan’s China-policy making Mainland Affairs Council.

“This is an important milestone for the government to further support democracy and freedom in Hong Kong,” Mr Chen said at the opening.

Taiwan shares with the Hong Kong protesters a deep antipathy for Beijing, which has never renounced the use of force to bring the island under its control.

In May, President Tsai Ing-wen became the first government leader anywhere to pledge measures to help Hong Kong people who leave due to what they see as tightening Chinese controls.

Mr Chen warned Beijing aimed to target people in other countries with the law, which covers permanent and non-permanent residents of Hong Kong.

“This not only targets residents in Hong Kong. It’s also an order issued by the Celestial Empire to people all over the world,” he added, referring to the Chinese government.

The law created an “opportunity” to win talent and capital from Hong Kong, Mr Chen said, although authorities would “strictly scrutinise” whether Chinese money was involved.

“We also welcome multinational companies to move their headquarters here,” he said, adding that Taiwan was reviewing its rules.

Beijing denies stifling Hong Kong’s freedoms and has condemned Taiwan’s plans to help people there.

On Tuesday, China’s Taiwan Affairs Office said the new law would “cut off the black hand” of the island’s meddling in Hong Kong.

Mr Chen declined to say how many people were expected, or the number of applications that had been received. His deputy, Chiu Chui-Cheng, said the new office would have about 24 staff with 20 inquiry hotlines, and officials have already received “many calls”.

-AAP