NSW has 31 new local coronavirus cases, with authorities warning numbers are likely to keep spiking for days before the full effects of the state’s lockdown are felt.

It is the highest daily tally yet since NSW’s latest outbreaks began with a Bondi airport driver in June.

Thirteen of Friday’s infections were out and about in the community before their diagnosis, sparking fears the virus is still spreading across locked down areas of Sydney, the Blue Mountains, Central Coast, Wollongong and Shellharbour.

“Last night’s figure of 13 is concerning, and that is something we are working to stress to the community – stay at home, do not leave the house unless you absolutely have to,” Premier Gladys Berejiklian said.

The daily total also includes four mystery cases, where health authorities have been unable to so far find the source of infection.

The results came from a bumper 73,000 tests in the 24 hours to 8pm Thursday.

Tweet from @NSWHealth

Ms Berejiklian said NSW was still “mopping up”, as current outbreaks reached 226 COVID infections on Friday.

“I am relieved I have to say that the case numbers were not as bad as what they could have been,” she said.

“The next few days are critical, because we know that what we’re doing until this point in time has been mopping up the last few days leading into the lockdown – we anticipated that.”

She expected to see the full impact of the lockdown from early next week. It is not due to end until July 9.

Friday’s new cases in existing NSW outbreaks included further infections linked to the West Hoxton “super-spreader” birthday party, the Joh Bailey hair salon in Double Bay, the Crossways Hotel in Strathfield South, Lyfe Cafe at Bondi Beach.

Chief health officer Kerry Chant said there were now nine cases across three “socially connected” Western Sydney households linked to the health workers whose infections were confirmed earlier this week.

There are also new concerns for venues across Sydney. They include:

• Bankstown swimming centre, Chapel Road, Bankstown
• Coles, Bondi Junction
• See an updated list of NSW exposure sites here

Dr Chant said exposure sites were shifting as the lockdown went on.

“We are seeing a move from hospitality venues, beauticians, hairdressers, to retail. The message is: Please don’t go out and about shopping in retail, in any setting if you have got a symptoms,” she said.

“It also highlights the importance, as people are moving around in shopping centres, please do assume that you are next to someone who may have COVID. Ensure you are wearing a mask at all times, and
ensure that it covers your nose and mouth, and also please keep your distance.”

This week, close to half of NSW’s new cases have been in people who have not been isolating. Dr Chant said whether Sydney’s lockdown ended on July 9 as planned depended on seeing the proportion of cases in people who had been in isolation throughout their infectious period growing.

“What we need to look at is increasing numbers of people isolated for the full period, the number of unlinked chains of transmission, the settings of those cases, and the context of these cases,” she said.

“All of these factors will influence our decision-making.”

Continued high levels of testing numbers were also crucial.

“We have had a sustained testing level that we have never seen before in the state,” Dr Chant said.

“The community response has been amazing, but we cannot get fatigued.”

SA reports another case

South Australia has reported another COVID-19 case linked to a miner who recently returned from the Northern Territory.

Premier Steven Marshall said on Friday a fourth child in the man’s family had tested positive for the virus.

All six family members, who all have the infection, have been transferred to Adelaide’s dedicated facility for positive cases and are not considered a risk to the wider community.

But Mr Marshall said South Australia would not reduce its current COVID-19 restrictions given the level of community transmission around the country, including NSW’s 31 new cases.

Those measures include a reduced density requirement for most venues, mandatory mask-wearing in high-risk settings and a limit of 10 people at family gatherings.

Mr Marshall said those measures were likely to remain until at least early next week.

-with AAP