The NSW premier is taking a "proportional response" to the COVID-19 scare in Western Australia and isn't changing the state's open border policy.
"It is a manageable situation at this stage and there is no reason why we will be altering our border situation," Gladys Berejiklian told reporters on Monday.
However, recent arrivals from WA will be screened after a Perth hotel quarantine security guard tested positive and two million people were put into a five-day lockdown on Sunday.
Travellers from WA who have arrived in the past week are also being told to self-isolate until Friday and confirm if they attended any of the venues listed on the WA Health website.
Any travellers who have been at places of concern must be tested and self-isolate for 14 days.
"NSW has kicked in to take those reasonable precautions, but we will not be closing our borders," Ms Berejiklian said.
"We don't know of any community transmission within WA apart from the security guard, so we are acting according to that risk."
NSW has long been at odds with WA over its approach to the pandemic, as the western state shut out most of the country for months on end.
But Ms Berejiklian resisted the temptation to gloat about the reversal of fortune as NSW recorded its 15th consecutive day without a single local case of COVID-19.
"It is not for me to suggest what other premiers should do," she said.
Deputy Premier John Barilaro was not as restrained, complaining that NSW has been getting plenty of free and frank advice from WA Premier Mark McGowan.
"When he was lecturing everyone else he needed to have a good look at his own system and, today, I think he should be embarrassed," he told Sydney radio 2GB.
Ms Berejiklian reiterated her belief that it was not possible to have an elimination strategy while allowing Australians to return home from overseas because "the disease can leak through the quarantine system and we have to accept that".
"The ... strategy must be zero community transmission and that is what we are working towards," she said.
"The key is how you respond to that when there is an outbreak, and that is where obviously the response is paramount.".
WA's COVID-19 woes - the first local infection in nearly 10 months - come as NSW travel freedoms expanded.
People from all parts of NSW are now free to visit Queensland after the Sunshine State dropped its border restrictions.
Queensland closed the border to 35 local government areas in Greater Sydney, Wollongong and the Central Coast during December's outbreak, causing chaos for festive season travellers.
But with NSW recording a long stretch without a local case, Queensland's border checkpoints are now being dismantled.
Border restrictions imposed on Greater Sydney by the ACT and Victoria also relaxed on Friday, while Tasmania and South Australia eased their restrictions on Sunday.
Six cases were identified in NSW hotel quarantine in the 24 hours to 8pm on Sunday.
Some 6023 people were tested in the reporting period, down from 8811 the previous day. NSW Health says it's concerned by the low testing rates.