Australian police are seeking to stop a Black Lives Matter protest from going ahead in Sydney this weekend, saying it poses coronavirus health risks.

Thousands are expected to attend the rally in solidarity with US protesters and to express anger about indigenous deaths in Australian custody.

But New South Wales (NSW) Police has applied for a court order to halt it.

Australian Prime Minister Scott Morrison criticised the protests on Friday, saying “don’t go”.

“Let’s find a better way and another way to express these sentiments, rather than putting your own health at risk, the health of others at risk,” he said.

Australia has recorded about 7,200 cases of the virus and rapidly flattened its curve since April. There have been no community transmissions in NSW for more than a week.

Protests have already been held in cities including Sydney, Perth and Canberra. Protests in Melbourne and Brisbane are still authorised to go ahead, despite warnings from health officials.

Since the killing of African-American man George Floyd in the US, Australians have protested against their own country’s disproportionate number of black deaths in custody.

At least 432 Aboriginal and Torres Strait Islander Australians have died in custody since 1991, according to data by The Guardian.

Why has the Sydney protest been challenged?

About 10,000 people have expressed interest in attending the rally on Saturday in the city centre.

Organisers have told attendees to wear face masks and personal protective equipment (PPE), and to try and maintain distance from others.

State Premier Gladys Berijiklian said the protest had been approved initially, but the rise in probable attendees had raised concerns about social distancing.

Both police and the government had asked the Supreme Court of NSW to have the protest “deemed illegal”, she told reporters.

“This is because the protesters could not guarantee adherence to the health orders. They could not guarantee safe social distancing,” she added.

The decision has been criticised by some as an attempt to stifle free speech.

The state’s police force was criticised earlier this week over the controversial arrest of an Aboriginal teenager in Sydney. Assistant Commissioner Mick Willing said he hoped the incident would not spark the level of violent demonstration seen in the US.

Australia has been slowly lifting its coronavirus lockdown restrictions. NSW has allowed many businesses to reopen, outdoor gatherings of 50 people to go ahead, and encouraged local travel.

The state recorded four new cases on Friday – all from returned travellers in quarantine.