The government on Friday urged people not to go to eight Covid-19 testing centres which are fully booked.

Two of them are in Sham Shui Po, two in Sha Tin, and the others in Ho Man Tin, Kwun Tong, Tai Kok Tsui and Mong Kok.

Certain testing centres have seen long queues recently, with people complaining they had to wait for hours to get a PCR test - a requirement for travelling to the mainland.

In a statement, a government spokesman reiterated that the city's testing capacity is sufficient to meet demand, noting that over 150,000 testing places were available for booking on Friday and Saturday.

The spokesman added that people can use the booking website to choose testing centres that are less busy.

He said priority at the centres is given to people with a booking and those without will inevitably need to wait longer. Evenings are the busiest times, he added.

About a hundred people were queuing at a testing station in Mong Kok on Friday morning, even before it opened.

A man surnamed Yang said he was going to the mainland on Saturday and got to the testing station early after friends told him they had earlier queued for two hours.

"If the mainland authorities can cancel the requirement for Covid tests, it will be more convenient for us to go back to the mainland. But this requirement is also a kind of protection for people in the mainland," he told RTHK.

A student surnamed Wang said he was heading back to the mainland ahead of the Lunar New Year and found the Covid test requirement to be unnecessary.

"I don't think we have to do the PCR tests. Wearing a mask is necessary, but PCR tests are useless. Doing a rapid antigen test before travelling is already enough," he said.

Some countries, such as the United States, Australia, France and South Korea, also require travellers from Hong Kong to take Covid tests before departure.

A woman surnamed Mak, who said she was going to the US, urged the government to make separate arrangements for people travelling to the mainland and those going overseas.

"Hong Kong government has the responsibility to take care of this mess. I hope that they can have a separate line, one for people going to the mainland and another one to other countries, so I don't have to stay here for hours with my kids," she said.

"I was here with my husband three weeks ago and it was empty. But because of the new policy and now the mainland border has opened up, it's a whole chaos again."