NSW vaccination hub to jab 30,000 a week

Four people who may have been exposed to COVID-19 at a Sydney quarantine hotel may be unaware NSW health authorities are urgently trying to contact them.

NSW Chief Health Officer Kerry Chant says up to 40 returned travellers and an unknown number of staff may have been exposed to the virus earlier this month and health authorities are yet to track down four people.

"We have managed to contact 36 of those individuals," she said on Thursday.

"We are urgently escalating contact with the remaining four."

The potential quarantine breach was revealed by NSW Health on Wednesday night after three returned travellers who stayed at the Mercure Hotel in Sydney were diagnosed with the same South African strain of the virus.

The travellers were family members who had stayed in connecting rooms on the 10th floor of the Mercure Hotel, while the third person stayed in another adjacent room.

Dr Chant said some hotel guests had since travelled to other states and territories and authorities there had been alerted.

Victorian health authorities identified six people as close contacts linked to the Sydney hotel and said they will be tested on Thursday.

Anyone who stayed on the 10th floor of the Mercure between April 7 and April 12, is being directed to get tested and self-isolate until 14 days after they left quarantine.

Staff potentially exposed will also have to self-isolate.

NSW Health authorities are still investigating how a breach may have occurred, but Dr Chant said the detection showed NSW's systems are doing their job.

"It's been pleasing to see that whilst we have detected these incursion events, they really haven't then led to further transmission," she said.

Health authorities said that a separate case of transmission between hotel rooms of the Adina Apartment Hotel at Town Hall was ongoing, and all contacts located so far had tested negative.

Meanwhile, Premier Gladys Berejiklian toured the state's first mass vaccination hub at Sydney Olympic Park in Homebush and said it would be open for business by mid-May.

"We're expecting this hub to be able to dispense around 30,000 vaccines every single week," she said at the new centre.

"This has not been done ever, to my knowledge, in NSW," Health Minister Brad Hazzard said.

All quarantine workers in NSW had now been vaccinated apart from new staff, he said.

"Of roughly 140,000 health staff, we have completed all but about 50-60,000 across all of NSW," he said.

GPs will remain the first port of call for those receiving the AstraZeneca jab, but those who want to be vaccinated in a state facility or don't have a GP will be able to get vaccinated at the hub.

Those with underlying health issues are particularly encouraged to go through their GPs.

The Homebush hub will predominantly administer Pfizer vaccines, which are trickier to store and distribute because they have to be stored at extremely low temperatures.

Some other vaccine sites across the state that have been distributing AstraZeneca jabs will be converted to allow them to dispense the Pfizer vaccine.

More than 180,000 COVID vaccinations have already been administered by NSW Health.