US president Donald Trump tells reporters he is considering a posthumous pardon for late boxer, Muhammad Ali, seemingly unaware that the supreme court overturned his Vietnam draft evasion conviction 47 years ago.

Donald Trump  said on Friday that he may grant a posthumous pardon to boxing legend, Muhammad Ali, seemingly unaware that Ali's conviction was overturned by the U.S. supreme court.

Departing for the G7 summit in Canada, the president told reporters at the White House he was looking at “thousands of names” of people who could be granted clemency.

Ali refused to enter the military during the Vietnam war and his local draft board rejected his application for classification as a conscientious objector. He received a draft-evasion conviction in 1967 and was stripped of his world heavyweight title.

“He was, look, he was not very popular then, certainly his memory is popular now,” Trump said. “I’m thinking about that very seriously, and some others.”

Ali was sentenced to five years in prison but he appealed and in 1971 the supreme court overturned his conviction, finding that the justice department improperly told the draft board Ali’s stance was not motivated by his religious beliefs as a Muslim. Trump’s gesture is therefore meaningless.

Ali’s lawyer, Ron Tweel, said: “We appreciate President Trump’s sentiment, but a pardon is unnecessary. The US supreme court overturned the conviction of Muhammad Ali in a unanimous decision in 1971. There is no conviction from which a pardon is needed.”

Muhammad Ali died two years ago in Scottsdale, Arizona, aged 74.