People in NSW should delay travelling to South Australia "as a precaution", as the state grapples with a potential second wave coronavirus outbreak, Gladys Berejiklian says.
The premier said NSW's borders "are completely open but if it's not essential travel think about whether you want to go in the next few days".
She offered the advice after the number of confirmed virus infections linked to the Parafield cluster in Adelaide northern suburbs grew to 20 on Tuesday. Another 14 potential cases are still to be cleared.
"We are confident that SA has it under control but we're just saying to our community ... if you can delay it for a few days unless you have to go there please do so," she told reporters on Wednesday.
It comes as federal authorities are keeping a close eye on Adelaide's coronavirus cluster, with more troops preparing to travel to South Australia.
The cluster in the city's north has grown to 20, with investigations continuing on another case.
There have been 11,000 tests conducted in the state over the past two days.
Federal Health Minister Greg Hunt praised South Australians for getting tested, encouraging people without symptoms to also be checked for coronavirus.
"We are looking for each and every person who might have in any way, shape or form been exposed to come forward," he told reporters in Canberra on Tuesday.
Mr Hunt said there were 100 Australian Defence Force troops on the ground in South Australia, with authorities meeting to map out how much extra support was needed.
They will be deployed immediately after decisions are made.
Meanwhile, passengers who arrived from SA on recent flights and trains are being contacted and having their temperature checked and asked if they had visited any areas of concern.
Health Minister Brad Hazzard said the advice had come from Chief Health Officer Kerry Chant who had been in contact with SA authorities.
"We have no intention at the present time of closing the border," he told Seven's Sunrise program.
"What we do want is people to minimise their travel. We don't want families to be separated unnecessarily and we don't want business to stop."
But Queensland, the Northern Territory, Tasmania and WA have slammed the gates shut on South Australia.
Victoria - which has now gone 18 days without new coronavirus infections or deaths - has increased screening for Adelaide arrivals.
The measures could set off another round of clashes between the Morrison government and the states, after senior federal politicians criticised Victoria's approach to easing its tough restrictions.
Treasurer Josh Frydenberg was scathing about the impact lockdown had on the mental health of Melburnians.
Western Australia Premier Mark McGowan offered a frank assessment.
"Some of those ministers, Mr Frydenberg and some of those characters, their behaviour was appalling," he said.
"(Victorian Premier) Dan Andrews did what he had to do ... the fact they undermined, criticised and attacked the whole way along during a period of extreme pressure was appalling.
"Steven Marshall has done the right thing and I support him in what he's doing. I'd urge everyone to support him in what he's doing."
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