LeBron James said there has been "no damn movement" for black Americans as he demanded justice for Breonna Taylor.

Superstar James spoke out on racial oppression after appearing for the Los Angeles Lakers in a 108-104 NBA scrimmage defeat to the Dallas Mavericks in Orlando.

In a passionate and erudite assessment of the state of American life, James said he and team-mates were firmly behind the drive for accountability after the shooting in March of African-American woman Taylor.

She died of gunshot wounds after three officers from the Louisville Metro Police Department executed a no-knock search warrant on her Louisville home, resulting in an exchange of fire between her boyfriend and the officers. It has been said by Taylor's family that she and her boyfriend suspected a break-in rather than a police raid.

James, also pointing to the death of George Floyd in police custody, insisted officers should pay for their actions.

"The same energy we had on the floor is the same energy we have toward having justice for Breonna Taylor and her family," he said.

"It's unfortunate. It's fortunate that we had the George Floyd video to see it, but is that what we need to see, a video of Breonna being killed, for people to realize how bad the situation is?

"I don't even believe they were at the right place. The cops weren't even in at the right place. They knocked down the wrong door and started doing what they do at that time and just started shooting away. And that's just not okay."

He added: "We want the cops arrested. Justice for Breonna Taylor is number one on our lists right now."

James spoke of reading about a black man who was trying to buy a bicycle for his son but had the police called on him.

“It's just heartbreaking. You guys don't understand," James said. "Unless you're a person of color, you guys don't understand. I understand you might feel for us. But you will never truly understand what it is to be black in America."

Speaking in a news conference, James also addressed the Black Lives Matter campaign, which has seen a light shone on racial injustices.

"A lot of people use this analogy that Black Lives Matter is a movement. It's not a movement. When you’re black, it's not a movement. It's a lifestyle," he said.

"This is a walk of life. I don't like the word 'movement' because unfortunately in America and in society there ain't been no damn movement for us."

He looked at America's political change, reflecting on how Barack Obama was in charge of the country four years ago. Without naming President Donald Trump, it was clear where James' message was directed.

"You know what's going on now. Is that progress?" he said.

"I think we can all say that’s not progress. The conversations being had right now and how many people are really listening or just having the conversations of trying to make things happen, that's progress. We got a long way to go."