Guo Zixin clearly remembers the heartbreak she felt when her pet poodle went missing four years ago.

"I couldn't stop thinking about where Maomao had gone," said the 25-year-old postgraduate student.

"Was she stolen? Was she on the streets? Was she being taken care of? Was she suffering? I had all these questions in my mind."

The incident left such an impression that she now fears the same could happen to her new four-legged companion, a husky called Bojue.

From next year, however, Gao's concerns, and those of many other pet owners, may be eased if a free animal identification program is rolled out across the capital.

Deputies to the Beijing municipal people's congress are now mulling a proposal to expand a pilot project that will see all registered dogs fitted with ID chips.

"The digital chip can assist residents in finding missing pets and decrease the number of stray dogs in the capital," said Qi Hua, a dog registration officer at Yuetan Park Police Station.

She explained that the information held on the device - breed, inoculation record and owner's address - can even act as a "pooch passport", making it easier for people to travel with their pets.

The Yuetan station is one of 10 in Xicheng district that have been running the pilot since 2007. Like in Shanghai and Guangzhou, the free chipping service is only open to owners who register their dogs, which in the capital costs 1,000-yuan ($160).

"It's very easy for veterinarians to implant the chip in a dog's neck," Qi said, although she added that the station has not kept a record of how many residents have taken up the offer.

The chip is the size of a grain of rice and is sold with a glass tube and a disinfected bag for 14 yuan. "It's in no way harmful to pets," said Zhu Junwei, a sales manager of Ruibaichuang Technologies, which makes the chip.

"We sell at least 4,000 sets a month nationwide and the number is rising," he said, adding that most units have so far been sold to urban farms.

Officials proposing to roll out the program across the city say they hope it will boost the number of owners who register their dogs.

Just 950,000 dogs are registered in Beijing, despite estimates of there being at least 2 million across the capital. Meanwhile, dogs bit more than 30,000 people last year, with a total of nine rabies cases resulting in death, official statistics show.

"Chipping dogs will allow us to improve our management of these animals," said Lei Decai, director of rural affairs for the Beijing people's congress. "It will also help authorities monitor the whereabouts of large dogs, which are banned from inner-city Beijing, as well as those that haven't received the proper vaccinations."

However, some owners have cast doubt on how effective the program will be in getting people to register their pets.

"The point of the chip is to boost registrations, but (even with the free chip) I can't see what benefits you get for paying the steep 1,000-yuan fee," said Zhao Yifan, 25, who works for Sina, the Internet company.

"If not getting the registration certificate means owners can't chip their dogs, I know that most of my friends won't do it," she added. "It's a shame, because there is a real demand there."