A Black Lives Matter demonstration is planned for next Tuesday despite NSW coronavirus health orders banning large groups of people.

"That's appalling," Mr Morrison told 2GB radio on Wednesday.

NSW Police Commissioner Mick Fuller has urged the public not to join the rally ahead of legal action to block it in the NSW Supreme Court.

The hearing will take place on Thursday afternoon.

Mr Morrison said people should listen to state government advice warning against protests, given their potential to spark a coronavirus outbreak.

"There's no special rule for people to not obey the law. What gives people a ticket to not obey the law," Mr Morrison said.

More than 4000 people have registered their interest in attending the rally, which aims to highlight the issue of Indigenous deaths in custody.

Organisers insist all attendees will be encouraged to exercise physical distancing, wear masks and use hand sanitiser.

NSW Premier Gladys Berejiklian echoed Mr Morrison's remarks.

"Irrespective of the issue, we need to follow the health advice - large crowds are a huge concern," Ms Berejiklian told ABC TV on Wednesday.

"We cannot allow that march to continue, unfortunately.

"If people feel strongly about that issue, they're welcome to express their views in different ways, but it's just not sensible at this time to expose yourself and others to the spread of the virus."

Australian Associated Press