The on-off heavyweight bout between Mike Tyson and Clifford Etienne is back on after the former champion said he is ready to fight on Tuesday.

Less than 24 hours after issuing a statement saying Saturday's fight was off because he had the flu and unable to train, Tyson had a sudden change of heart on Tuesday and was on a chartered flight from Las Vegas to Memphis.

"It's on," said Tyson spokesman Fred Sternberg. "Mike woke up this morning and said he wanted to fight.

"He said, 'I feel much better, I can beat this guy, let's do it this weekend'."

The 10-round bout at the Pyramid Arena had been postponed on Monday after Tyson, whose behaviour had become increasingly erratic in the weeks leading up to the fight, failed to arrive in Memphis.

Fight promoter Showtime then postponed the bout, raising questions about the 36-year-old's boxing future.

Showtime said in a statement on Monday the TV network had no immediate plans to reschedule the fight, leaving a planned rematch with heavyweight champion Lennox Lewis also in doubt.

Lewis knocked out Tyson in the eighth round of their previous encounter in Memphis last June and had scheduled a rematch, dependent on how Tyson fared in the Etienne bout, for June.

Tickets sales for the fight had been described on Monday as, "good" with about 10,000 having already been sold.