Thousands of protesters are expected at the rally on Saturday, and Deputy Commissioner Shane Patton says if that happens, each organiser will be fined $1651 because of COVID-19 restrictions.

Fines could also be issued to individuals, according to a police statement.

"In the exercise of police discretion, those who intentionally break the law will be held to account," the statement said.

Police previously had said they were unlikely to fine individual protesters who attend the rally.

"We will be issuing infringements to the organisers if this goes ahead and if it's greater than 20 people in breach of the chief health officer's guidelines," Mr Patton said on Friday.

"They (guidelines) are in place to prevent the spread of this disease."

Protest organisers Warriors of the Aboriginal Resistance stressed safety of the community was paramount while insisting the protest will go ahead as planned.

They asked attendees to wear masks, bring hand sanitiser and protest in groups of 20 while remaining 1.5m apart.

Protesters have also been encouraged to self-quarantine for a few weeks afterwards.

"Governments and police are trying to deflect from their responsibility," WAR organiser Meriki Onus said.

"Protest is not a choice when so many of our people are murdered at the hands of police and prison guards."

The protest will be held outside Victoria's Parliament House.

It is one of a number to be held across Australia in solidarity with the Black Lives Matter movement in the US and calling for an end to Aboriginal deaths in custody.

The BLM movement has sparked rallies against police violence in the aftermath of African American George Floyd's death at the hands of white officers in Minneapolis.

Premier Daniel Andrews urged Victorians not go to the protest, saying there were other ways to make the important point of showing support for the cause.

"Big events are not allowed. Big events are not safe. Big events will do nothing but spread the virus," he said on Friday.

"This is not an ordinary Saturday in June, we're in the midst of a global pandemic."

The warnings came after Victoria's Chief Health Officer Brett Sutton said those attending would be at risk and would pose a health threat to the broader community.

Professor Sutton admitted transmission levels in the state were at extremely low levels, but noted the chances of the virus spreading were higher in a crowd.

"I understand the passions that people will have in relation to this and the desire to protest, but my focus has always been on the health and wellbeing of people, and that includes for the protesters themselves."

The organisers recognise the health risk but argue the need to stand up at Saturday's event overrides that concern.

"The risk is great, I don't deny that. I am an at-risk person," indigenous academic Marcia Langton told ABC Radio.

"I do appeal to everybody to wear masks and social distance at the protest. But at the same time, every time an Aboriginal person goes out on the street, we are at risk."

Australian Associated Press