The delay will be until at least Tuesday morning as the judge contends with a last-minute order by a higher court to reconsider adding an additional murder charge.

The trial had been scheduled to begin on Monday with the screening of jurors to weigh murder and manslaughter charges in a case seen as a referendum on police violence against black Americans.

Chauvin appeared in court dressed in a navy blue suit and tie, a white shirt and a black face mask, jotting notes in a yellow legal pad on the table before him.

Judge Peter Cahill of the Hennepin County district court set aside three weeks for jury selection alone, mindful of the difficulties finding impartial Minneapolitans in a case that has convulsed a nation and in which an image of the victim -- a selfie of Floyd faintly smiling -- has become an international icon of racial justice.

But that was delayed at the urging of prosecutors after the Minnesota Court of Appeals told Cahill in an order issued on Friday he must reconsider prosecutors' request to also reinstate a third charge, third-degree murder, over the defendant's objections.

Eric Nelson, Chauvin's lead lawyer, told the court on Monday that Chauvin would soon ask the Minnesota Supreme Court to overturn Friday's order, a process that could take weeks, although he saw no reason for that to delay jury selection.

But prosecutors from the Minnesota attorney-general's office urged the court to delay jury selection until the appeal was resolved.

"We're not doing this to interfere, to slow this down, but it is a very important matter," Matthew Frank, an assistant attorney general, told the court. Prosecutors feared picking a jury when the number of charges was still unresolved could make it easier for Chauvin to appeal a verdict later, Frank said.

Cahill declined, repeatedly saying he believed he was entitled to at least begin seating jurors unless a higher court ordered him not to. Prosecutors then said they would ask the Appeals Court to intervene to delay the trial. Cahill suspended jury selection until at least Tuesday.

Chauvin, 44, is charged with second-degree murder, which carries a sentence of up to 40 years in prison, and manslaughter.

He was released from jail on a $US1 million ($A1.3 million) bond in October.

The medical examiner ruled that Floyd's death was a homicide caused partly by police restraint holds.

But the autopsy report also noted that Floyd had recently ingested the opioid fentanyl, and Chauvin's lawyers contend that an overdose was the main cause of death.

Australian Associated Press