In response to the worries of residents in Beijing without permanent residency cards, authorities said the city's first public bike rental service will be open to all people.

"As the service is in trial operation, the registration system can only recognize the second-generation ID cards held by Beijing residents with hukou (residential permit) at the moment," the Beijing Information Office said on Sina Weibo on June 18.

Public rental bikes placed outside a subway station in Dongcheng district of Beijing city, June 17, 2012. [Photo/Asianewsphoto]

"But opening it to all people in Beijing is our next step. So please be a little more patient."

The first batch of 2,000 bikes have been stationed in 63 places with high traffic flow in Beijing's Dongcheng and Chaoyang districts since Saturday, aiming to provide a green and low-carbon transport service to residents, the Beijing Municipal Commission of Transport said on its website.

The service will be extended to all districts in Beijing, and 50,000 bikes will be in use in 1,000 designated service places by 2015 to cover major towns, transportation hubs and streets, the news release said.

Residents can use the bikes free the first hour, and pay 1 yuan (16 cents) each hour afterward. Maximum expense for a day's use is 10 yuan and a user can rent the bike for three days at most every time.

To get access to the service, a resident has to register with an ID card and prove that he holds a hukou, according to the regulation, which sparked controversy among some people.

More than 19 million people live in Beijing, but only 12 million had a hukou in 2010, according to a survey last year.