Under-30s can register for a Pfizer COVID-19 vaccine in Canberra as the city records another 16 coronavirus cases, taking its outbreak to 137.

All but three of Monday’s cases are linked to existing infections or exposure sites. Three people were infectious in the community.

The ACT is also letting about 64,000 people between 16 and 29 register for a Pfizer vaccine.

Chief Minister Andrew Barr anticipates bookings will open as Pfizer supplies increase, hopefully, next month.

About 21,000 people in that age group have already been vaccinated either with AstraZeneca or, because of priority eligibility, Pfizer.

A 10th disability support worker is confirmed to have the virus, bringing cases in that sector to 15. Four people with disabilities and a tradie are also infected.

The Condamine Court public housing complex is listed among more than 360 exposure sites.

The Australian National University will also join the list after a case was confirmed at the campus.

Overall, four hospital patients have COVID-19. Two are in hospital for other reasons with another two being treated for the virus. None of them need intensive care.

More than 3700 tests were conducted on Sunday.

More than 13,500 close contacts and 6100 casual contracts are in quarantine.

Federal parliament returned on Monday with reduced numbers as many politicians attended remotely.

Canberra is halfway through its three-week lockdown scheduled to run until September 2.