He has at least two significant Samoan designs inked on his super-sized body but NRL star-turned boxer Nelson Asofa-Solomona says he never seriously considered representing the Pacific Islanders.

As Samoa prepare to tackle Australia in the Rugby League World Cup semi-finals, Asofa-Solomona has a huge fight of his own in Sydney on Friday night against fellow former NRL premiership winner Paul Gallen.

But the two-metre-tall powerhouse may have disappointed Samoan fans with his surprise snubbing of the tiny nation where both his parents were born before moving the family to New Zealand.

Asked by AAP who was going to reach the final of the global showpiece, the two-time premiership-winning Melbourne Storm enforcer didn't even offer a tip for the Samoa game before pledging his 100 per cent allegiance to the Kiwis.

"I'd love New Zealand to be in there, obviously," said the 16-Test former Kiwi international.

"I've played for them and we've been through the trials and tribulations for the last two World Cups and I know how hard it's been for them and I would love for a bit of a success story for those boys to raise that trophy for New Zealand."

The 30-year-old said "of course" he'd been asked to play for Samoa.

"Probably a couple of years ago," he said.

"Actually, probably like halfway through my career, throughout the duration of my career, I've been asked.

"But, no, I wanted to stick solid to New Zealand. I didn't want move away from my decision. Once I pick, I stick."

Asofa-Solomona's fierce loyalty to New Zealand comes after a swathe of fellow Pasifika-eligible players, including Samoan stars Hamiso Tabuai-Fidow and Payne Haas, jumped ship from Australia or the Kiwis to represent their family's heritage.

Showing a surprising soft side, despite his rival on Thursday branding the former Cronulla and NSW State of Origin captain "selfish", Gallen declined to throw any more flak at Asofa-Solomona after a bitter build-up to Friday night's heavyweight grudge match.

"Mate, he's doing his best for himself and that's all we ever do in life, so I'm not trying to talk him down," Gallen said.

"But the facts are the facts. He's had three or four fights now and as a pay-per-view number.

"Why have they got me back ? I don't really care to be honest. I'm just worried about tomorrow night.

"That all that matters to me. He can do what he wants in the future. I've got no animosity towards him doing that.

"I wish him all the best, but I'm here to destroy him tomorrow night. I'm here to finish him tomorrow night."

Australian Associated Press