Floyd, a 46-year-old African-American man, died after a US police officer kneeled on his neck for nearly nine minutes, in Minneapolis in the US state of Minnesota last month.

Four officers have been arrested, with one facing murder charges, and the others facing charges for aiding and abetting.

Biden formally clinched the US Democratic presidential nomination on Saturday, setting him up for a bruising challenge to Trump that will play out against the unprecedented backdrop of a pandemic, economic collapse and civil unrest.

In an opinion article published in the Los Angeles Times on Saturday, Biden spoke of the need for "long-overdue, concrete policies to reverse systemic racism".

"If elected, I am committed to establishing a national police oversight commission within 100 days of taking office," the former vice president promised.

"We need to implement real community policing and ensure that every police department in the country undertakes a comprehensive review of their hiring, their training, and their de-escalation practices, with the federal government providing the tools and resources needed to implement reforms," Biden said.

"But, we cannot wait for new leadership to make reforms," he added.

He called on Congress to "take action immediately" to outlaw choke-holds, stop the transfer of weapons of war to local police forces, improve oversight and accountability and create a model standard on the use of force by police officers.

On Twitter, Biden reiterated his call for change, writing: "We need justice. And we need real police reform to ensure this never occurs again."

"I promised George Floyd's family that he wouldn't just become another hashtag," the 77-year-old added.

Australian Associated Press