WASHINGTON (AFP) - US President Donald Trump's son-in-law and senior aide Jared Kushner on Thursday (Aug 27) criticised a walkout by NBA stars protesting against racism and police brutality, saying they were fortunate to be rich enough to take the night off.

The Milwaukee Bucks led the boycott over another police shooting of a black man, forcing the league to halt its playoff schedule and prompting a wave of walkouts in other sports.

The NBA postponed its Wednesday evening fixtures after the Bucks refused to play the Orlando Magic in protest over the shooting of Jacob Blake in Wisconsin on Sunday.

"The players in the NBA... have the luxury of taking a night off from work - most Americans don't have the financial luxury to do that," said Kushner in an interview with the Politico news site.

"I think that it's nice that they're standing up for the issue but I'd like to see them start moving into concrete solutions that are productive."

Los Angeles Lakers superstar Lebron James voiced solidarity with the Bucks.

"WE DEMAND CHANGE. SICK OF IT," James, who has launched several anti-racism initiatives, tweeted.

When told of James' record of anti-racism work, Kushner said that "if LeBron James reached out to the White House and we reach out to him, we're happy to talk with him and say, 'Look, let's both agree on what we want to accomplish.'"

The NBA postponements marked a dramatic escalation in the league's calls for social justice, which have reverberated across US sport since the killing of unarmed black man George Floyd by Minneapolis police in May.

Large nationwide protests have been marked by violence and looting.

"I do think that peaceful protest has a place and it has importance," Kushner said.

"You don't improve wealth equality by rioting and burning down stores."