NSW has reported seven new cases of COVID-19 in returned travellers staying in hotel quarantine, with the premier admitting an outbreak in outer Melbourne is a concern.
The new NSW cases came from more than 11,800 tests done in the 24 hours to 8pm on Sunday, with no patients currently in intensive care.
There have been 3184 COVID-19 cases to date in NSW.
Three new COVID-19 cases were on Sunday reported in NSW, including a 34-year-old man who was part of an overseas cargo airline crew who became unwell in transit.
NSW Health's Dr Michael Douglas said on Sunday close contacts of the airline worker had been identified and further investigations were underway.
Some 3391 symptomatic returned travellers have been tested in hotels since March 29, with 107 of those - about three per cent - testing positive to the virus.
NSW Health is still discouraging travel to and from areas of Melbourne with COVID-19 outbreaks and for any recent returnees from Melbourne to avoid aged care facilities.
Victoria on Monday reported 75 new cases of COVID-19 and NSW Premier Gladys Berejiklian on Monday told reporters the escalating case load was an issue.
She emphasised the NSW-Victoria border would not shut but warned all residents of greater Melbourne to steer clear of NSW until community transmission was reduced.
"The exponential increase in the number of community transmissions in Victoria is a concern but NSW is providing enormous support to Victoria," Ms Berejiklian said.
She also warned the Queensland government against reneging on its prior commitment to ease state border restrictions in July, saying it would hurt Queenslanders and their engagement with NSW, Australia's largest state economy.
The Queensland government is set to announce its decision on border closures on Tuesday.
Following the spike of cases in outer Melbourne - where the number of new coronavirus diagnoses has grown by double digits every day for more than a week - NSW has announced it will turn away football fans from its southern neighbour.
NRL and AFL spectators trying to enter NSW stadiums from Wednesday are likely to be required to show their driver's licence to prove they're not from Victoria.
Meanwhile, the state government said on Sunday visits to parklands and gardens around Sydney have increased during the COVID-19 pandemic.
Australian Associated Press