The organisers of a Black Lives Matter protest have vowed to go ahead with the rally in Sydney today, despite it being deemed illegal by the Supreme Court.

Speaking on Today, Premier Gladys Berejiklian urged those planning to attend the protest to think about the health of their loved ones.

"If you are not worried about yourself think about your loved ones you could be infecting and causing enormous harm to," she told the morning show.

"We are appealing to people conscientious and the ethical standards say that you should not be out there."

The premier urged people to find a different way to express their views on the issue at hand, adding the state was not under "normal" circumstances.

"In NSW we are in a very, very critical point. If we get through the next couple of weeks managing to control the spread, our prospects of having a very positive experience in the next little while are much greater," she said.

"It only takes a few cases for this thing to go out of control. We have seen that in Victoria. We don't want it to happen in NSW.

"I am just appealing to everybody think about another way to express your views."