SYDNEY (REUTERS) - Thousands of people protested in Sydney on Tuesday (June 2) over black American George Floyd's death in US police custody, as Australian police faced questions about use of force during the arrest of a teenager of aboriginal descent.

The protesters defied restrictions on public crowds imposed because of the coronavirus outbreak to gather at Hyde Park in Sydney's central district, Reuters witnesses said.

Protesters, some wearing surgical masks, marched peacefully towards government buildings, holding signs saying "I can't breathe!" and chanting "black lives matter" and "take a knee" while mounted police stood by.

"This is everybody's problem," Ms Kira Dargin, an aboriginal Wiradjuri woman at the protest, told Reuters.

"As a black woman, I'm tired of seeing my brothers go down. As a black mother, I fear for my child. Got to stop."

Mr Floyd died last week after a white policeman pinned him down with his knee for nearly nine minutes after arresting him.

In Sydney, an investigation has been opened into the arrest of a 17-year-old of aboriginal descent after video footage appeared on social media showing him being handcuffed and kicked to the ground after an argument with police.

The constable involved has been put on restricted duties while the investigation takes place.

"This is not the United States of America," Assistant Commissioner Michael Wiling told reporters. "We have very, very good relations with our local community. I'm concerned that people will pre-empt the outcomes of the investigation and draw conclusions prior to that."