NSW records 30 new COVID-19 cases on first day of lockdown

New South Wales has recorded 30 new community cases of COVID-19 as Greater Sydney and surrounds enter their first full day of lockdown.

All of today's new cases have been linked to existing clusters but 19 were not in isolation while infectious.

The new infections have sparked concerns around potential exposures at a major western Sydney Hospital, an inner-west seafood wholesaler and a number of interstate flights.

READ MORE: Five Virgin flights sent into isolation after crew member tests positive

It is the highest number of daily cases recorded since the start of the Bondi outbreak, but Premier Gladys Berejiklian warned further increases were likely in the coming days.

"We are seeing that people in isolation, unfortunately, would have already transmitted to all their house contacts," Ms Berejiklian said.

More than 52,000 coronavirus tests were conducted yesterday, down slightly from just over 55,000 the previous day.

LIVE UPDATES: Darwin to go into lockdown as four new cases recorded

The number of cases connected to the burgeoning Bondi cluster now stands at 110, while two other community cases are under investigation.

There is also one new case who caught the virus from a Northern Territory gold mine worker revealed as a positive case yesterday.

The miner is believed to have contracted the virus while in hotel quarantine in Queensland.

That NSW resident has since travelled back to their home in the Hunter New England region of NSW and was in quarantine while infectious.

READ MORE: Two new Queensland cases 'visited a lot of sites' while infectious

One of their household contacts has also since tested positive.

Anyone who worked at the mine in the Northern Territory between June 18 and 26 and returned to NSW should immediately isolate and call NSW Health to arrange urgent testing.

If they have any symptoms, the households of those individuals are also being asked to isolate.

In Sydney, a seafood wholesaler in Marrickville is emerging as a key venue of concern.

Ten of today's 30 new cases are linked to the Great Ocean Foods wholesaler, where two staff members worked while infectious.

NSW Health is upgrading its warning for the distributor.

Anyone who visited the Marrickville site or received a delivery from them at any time from June 21 through to June 25 to immediately isolate, call NSW Health on 1800 943 553 and get tested.

Their household contacts must also isolate with them and await advice from NSW Health.

READ MORE: All the latest Sydney COVID-19 exposure sites

In a separate case, an infected individual went to the vaccination centre at Westmead Hospital, Chief Health Officer Dr Kerry Chant said.

She assured people all healthcare workers were wearing masks, social distancing was in place and the area where the person went has been cleaned.

"As a precaution, we are very conservative, we have called the people that attended that vaccine centre in a period before and after the case and also looked at healthcare staff that may have been close contacts," Dr Chant said.

While contact tracers race to trace new infection sources and isolate those exposed, NSW Police is ramping up its crackdown on anyone found breaching lockdown restrictions now in place across Sydney and its surrounds.

Fifteen people were fined for breaches of restrictions, including a group of people who "converged" on a Woolworths in Kellyville, a Sydney family who travelled to the Hunter for a sporting event and an Illawarra cafe owner and staff who refused to wear masks.

You can find out more details about how to book your vaccine through the Federal Government health site here.