North Queensland MP Bob Katter has accused the NRL of insulting and offending fans by choosing American artist Macklemore — a vocal supporter of same-sex marriage — as its half-time act.

Mr Katter echoed former prime minister Tony Abbott, who backed calls to stop Macklemore performing his hit song, Same Love.

Mr Katter, a league fanatic, is heading to the grand final this weekend to support his team, the North Queensland Cowboys, but says he is outraged and that NRL fans won't be happy.

"If they [the NRL] take the most sacred day of the year, outside of Christmas, and use it to promote their sexual proclivities, that is an insult and an offence to every single follower of rugby league in this country," he told 7.30.

One of the songs that will be played in Macklemore's half-time act is Same Love, which advocates LGBTI rights, including same-sex marriage.

On Thursday, NRL CEO Todd Greenberg backed his decision to bring the rap artist to Sydney.

"I don't regret choosing Macklemore," he said.

"I think it's one of the bravest decisions we've made for pre-match entertainment, but people will be the judge of that after the show on Sunday."

Sorry, this video has expired The Tony Abbott v Macklemore barney is another chapter of politics and sport overlapping.

Bob Katter says Greenberg's move has "besmirched" the game.

"I mean, this CEO bloke who made this decision, mate, it's tantamount to seeping sewage into the debutante ball."

And Mr Katter says he does not want to see Macklemore take the field at half time.

"They said of the Americans during the war that there were three problems with them: over-sexed, over-paid and over here," he said.

"Well, this little bloke, Macklemore, or whatever his name is, is coming over here. Well mate, go home, we don't want you here.

"The people that will be there at this game don't want you."

'This is about saving lives': NRL great Ian Roberts

Sorry, this video has expired Ian Roberts speaks out on same-sex marriage

Former rugby league great Ian Roberts was the first NRL star to come out as gay.

He wrote to Greenberg, asking the sport to back the same-sex marriage campaign.

"I love the game, and I just know the impact the sport has on our community, and for the AFL to be on board so full-heartedly and not for the NRL to be on board would be a travesty," he told 7.30.

"There was no hesitation which was wonderful."

Roberts said the same-sex marriage debate was about equality and mental health.

"The whole thing about marriage equality and I don't say this lightly … it will save lives," he said.

"There are kids out there in the suburbs who are really struggling with this, and it's a horrible thing to say but it needs to be said: there are kids killing themselves in the suburbs.

"When you get people like George Christensen, Cory Bernardi and Tony Abbott carrying on about what they term as freedom of speech and freedom of religion, I can promise you that all these young kids dealing with their sexuality at the moment, they mightn't hear much on the news reports but I can promise you they hear it every time those guys speak up."

Roberts said there was nothing wrong with the NRL or AFL weighing in to the same-sex marriage debate.

"More power to those sporting bodies for taking a stance for inclusion," he said.

"I fail to see how that can be seen as a political stance — it's a social issue.

"What the league's doing this weekend with Macklemore, it's a wonderful, wonderful experience for anyone who is not used to being included."

'Could be a very powerful moment'

Matthew Mitcham says the NRL crowd will love Macklemore singing Same Love. ( ABC News: Nic MacBean )

Diver Matthew Mitcham, who was the first openly gay athlete to win an Olympic gold medal, said he was surprised the NRL and AFL had come out in support of the Yes campaign.

"Sport has always been one of the last bastions of conservative police," he told 7.30.

"It's really great to see that both the NRL and AFL are really committed to inclusion. It's part of their mission statements it to be inclusive."

He said the NRL grand final crowd would probably "love it" when Macklemore sang Same Love.

"It could be a very powerful moment, I'd like to hope it will be."