The state leader was asked at a at a media conference in Sydney when the frontier would be free to travel, following reports that it could remain shut beyond Christmas.

"We're not locking ourselves into a timing," Ms Berejiklian said.

"The timing that we're locking ourselves into is what is safe for NSW and the rest of Australia and that's what matters to us."

Ms Berejiklian again linked any reopening to what may happen after Victoria lifts its so-called ring of steel between Melbourne and regional areas on November 8.

"We know that when you're in a lockdown it is easy to control the virus, the real test is once you ease those restrictions and it takes at least two weeks for us to see what that will do," she said.

Ms Berejiklian added: "Once we see evidence of that for about two or three weeks after the restrictions are eased well then we will rely on the health advice."

The Premier also flagged concerns about the monitoring of COVID-19 through QR codes in Victoria, but noted a range of factors would be examined for the opening.

"We'll be sensible about the Victorian situation if we feel the health advice says to us 'look they've been open for two weeks, these restrictions have been eased, they've got the virus under control, they've improved their systems', well then it's happy days," she said.

"But until that time I won't expose NSW and to be frank Australia because if NSW goes down so does Australia and I don't want to be in that position."