Gladys Berejiklian says what's happening in Victoria with COVID is "really concerning" but her position on keeping the border open remains the same.

"My heart goes out for the people of Victoria," she told reporters on Monday.

"They've been down this path before, and I can't imagine what it would be like to go through so many instances when your life is so massively disrupted," Ms Berejiklian said.

She "can only imagine how difficult it is" for Victorians who are part way through a seven-day lock down, the fourth one since COVID started.

She refused to be drawn on whether she would have locked down if NSW had a similar cluster size, saying "you really have to take every outbreak on its merits".

Despite nearly 300 exposure sites in Victoria, it doesn't change the government's thinking on borders.

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"Victorians aren't allowed to move within five kilometres of where they live anyway, and we have some guidelines around border communities so that we're not adversely impacting residents on either side of the border."

"When Victorians aren't allowed to travel more than five kilometres outside of where they live that obviously does not concern us because they can't travel and get to NSW."

"That's why I say to the other states when Victorians aren't allowed to leave their homes you shouldn't worry about your own borders."

However, she warned people from NSW should not be travelling to Victoria.

"We've said don't go unless it's absolutely essential .. I mean you can't do anything down there anyway... unless it's life or death or family grieving we don't want anyone down there."

Ms Berejiklian also called on NSW Labor - which is currently without a leader - to focus on the people of NSW and not internal skirmishes.

Former Labor Leader Jodi McKay resigned from the position on Friday, citing the need for unity in her party.

"I say to the members of the opposition I wish you could walk in my shoes for a day and see what it's like to have to run a state during a pandemic," Ms Berejiklian said.

There have been no new local cases of COVID recorded in NSW to 8pm on Sunday, while almost 1.3 million vaccinations have been administered.

Australian Associated Press