There have been no new locally-acquired COVID-19 cases in the 24 hours to Monday night, but authorities expect this may change.

Premier Gladys Berejiklian has said more than 7300 tests were conducted in NSW in that same period.

But she said residents should brace themselves for new cases after it was revealed two COVID-19 cases from Brisbane visited various venues in Byron Bay at the weekend, before they were diagnosed but while they were infectious.

"We're asking everybody to be alert, to make sure you get tested if you have the mildest of symptoms," Ms Berejiklian said.

"Please also make sure that if you've returned to NSW you comply with whatever lockdown provisions are in place in Brisbane.

"You have to follow that here in NSW but for those exemptions that are available."

Ms Berejiklian said she was hopeful there would not be a new outbreak in NSW, but she expected there would be.

"I hope that we won't have any cases that emerge in NSW but I won't be surprised if we did so we need to brace ourselves," she said.

She said NSW chief health officer Dr Kerry Chant was "in regular contact with the Queensland authorities".

"We are expecting more cases from Queensland and hopefully most of those cases will be people in isolation although we have to assume this is an evolving situation," Ms Berejiklian said.

"If you have attended any of the venues in NSW which NSW health has identified get tested and stay home for the full 14 days.

"We also expect you to take a second test toward the end of your isolation period."

Dr Chant said in the past day, NSW recorded five new COVID-19 cases acquired overseas.

She said of the hens party which involved the two positive cases who visited Byron Bay, one is a NSW resident but is currently staying in Queensland and is being tested there.

"I'm urging anyone who was in Byron on that weekend to please be particularly vigilant as to any updated information," Dr Chant said.

"Were asking people from greater Brisbane not to visit aged care facilities or hospitals or disability care homes."

She said "essential visits" and "essential end of life care" visits were permitted but people must alert the facility's staff and wear a mask.