Hongkongers who are travelling and living in mainland China can now apply for a temporary digital permit to travel by air and train within mainland cities if they lose, damage, or forget their permit.

Under the policy announced by the National Immigration Administration (NIA) on Thursday, the temporary digital mainland travel permit will be valid for seven days after application.

Residents can apply for the temporary permit via the NIA’s 12367 mobile app.

“Under the new policy, Hong Kong, Macau and Taiwan residents who lose, damage, or forget to carry their travel permits can apply for a temporary electronic permit valid for seven days, allowing them to board flights and trains within mainland cities.” the NIA said in a statement via Xinhua News Agency.

The NIA has also launched a verification service linking travel and residence permits. People can also access this service via the 12367 app.

The linkage proof between the permits is for those who are trying to access finance or internet services on the mainland.

The NIA said they will continue to improve relevant measures to provide "accurate and equally convenient" services for SAR residents.

A Federation of Trade Unions lawmaker Kingsley Wong welcomed the NIA announcement, but pointed out the arrangement only allows travellers to use two modes of transport.

"I hope temporary electronic permits can be used for immigration in the future," he told reporters at Legco.

"If Hong Kong residents lose their permit on the mainland, I hope they can also apply for a temporary electronic permit, allowing them to return to the city, instead of wasting their time waiting at border control points."

And Hong Kong's delegate to the National People's Congress Standing Committee Starry Lee said the arrangement helps facilitate travel between mainland cities.

But she hopes central authorities could consider permanent electronic permits for Hong Kong residents in the long run.

"This will make it more convenient for people with travel permits who reside and live on the mainland," she said.

"The numbers of a mainland travel permit and a mainland identity card are different, and sometimes it may be inconvenient and time costly to deal with different situations."