New Zealand heavyweight David Tua says he has shaken off a calf muscle injury and will fight at a trimmed-down weight against Belarusian Alexander Ustinov next month.

Tua is confident the bout in Hamilton on November 16 will see him at his lightest fighting weight since tipping the scales at 107kg ahead of his win over compatriot Shane Cameron in 2009.

He was heavier for subsequent fights against Nigerian Friday Ahunanya and Americans Demetrice King and Monte Barrett (twice) but says he has trained hard and should weigh between 105kg and 110kg against Ustinov.

"Physically I am in a great space right now," he said.

"There is still a bit of work to be done. I can't get too relaxed. The key now is to stay focused."

Tua was scheduled to fight Ustinov in August before sustaining the calf injury.

He says he has fully recovered and the extra time to prepare has proven valuable.

An Olympic bronze medallist in 1990, 40-year-old Tua boasts a professional career record of 52 wins from 58 fights, including 43 knockouts.

There have been two draws and four losses, which includes his last fight, more than two years ago when Barrett won a unanimous points decision in Auckland.

The 2m tall Ustinov, 36, has lost just once in 29 fights and has knocked out 21 opponents.