UFC heavyweight Mark Hunt is back in the fold and about to return to the octagon with a fight against Alistair Overeem in Las Vegas on Sunday, but a burning sense of injustice remains.

He is a man on a mission to clean up the sport of MMA from what he says is the scourge of performance-enhancing drugs.

The New Zealand-born Hunt, who is based in Sydney, missed three fights after his defeat on points against Brock Lesnar in UFC 200 last year and at one stage doubted he would fight for the organisation again such was the disgust he felt after Lesnar tested positive for a testosterone booster.

Lesnar was Hunt's third opponent to test positive for drugs, and his anger remains strong. The American, a WWE star, announced his retirement from MMA a fortnight ago, and Hunt is pursuing legal action against him.


It means some of the joy has been taken from Hunt's return in UFC 209, a card headlined by a rematch between welterweights Tyrone Woodley and Stephen Thompson in the bright lights of the gambling mecca.

For Hunt, who will turn 43 on March 23, a return to the octagon is tainted by a disappointment that will probably stay with him for the rest of his career.

"To be honest, I should be feeling really excited about fighting this weekend and being back in Vegas where everything happens ... but I'm kind of upset being here because of what's happened," he told the Herald.

"I've missed out on three fights - that's $3 million or $4m that me and my family should have got - so why did I miss out on that money? I did nothing wrong... yet I'm the one being punished, I'm the one being ostracised."

A victory for the big-hitting Hunt, who has a 12-10-1 record, would be also complete a revenge mission of sorts.

The Super Samoan lost to Overeem in 2008 and a victory would put him back in the title frame. Overeem, 36, will have a reach advantage and his judo background also makes him a big threat on the floor. He has 19 wins by submission alone.

In Hunt's favour is his punching ability, toughness and ability to adapt. But he must also keep his emotions in check; he said he would sue Overeem if the British-born Dutchman failed a drugs test following their fight. "If he's cheating then I'll sue him, and I'd advise every other fighter to do the same."

In July, weeks after his loss to Lesnar, Hunt told the Herald he was attempting to set up a fighters' union. He said today there was a groundswell of support.

"Some of them [fighters] are trying to implement the "Ali act" which is a bit more transparency throughout the company ... and trying to create an even playing field. I've said it before, someone could die in the ring if they come up against someone using steroids. It should be a criminal act where the guy goes to jail."

Hunt, who said he had enjoyed a good camp on the Gold Coast, added the UFC had a duty of care to provide a safe working environment in what was already an extremely dangerous occupation.