Melbourne are set to lock down man mountain Nelson Asofa-Solomona with a long-term contract extension, and it's a particularly special Craig Bellamy spray over a backfiring vegan diet that sums up exactly why the rugby union prodigy wants to stay at the Storm.

NRL.com understands that the Storm are in the final stages of closing an upgraded deal for the 200 centimetre, 123-kilo Kiwi international, with what's believed to be a three-year extension tabled and agreed to by Asofa-Solomona.

Already contracted until the end of next season, the new deal would keep one of the game's most damaging forwards in purple until 2022 and is expected to be announced once Sunday's grand final clash with the Roosters wraps up his season.

To hear both Storm officials and Asofa-Solomona talk about his loyalty to the club in the face of serious All Blacks interest as a seventeen-year-old, rivals are pushing the proverbial uphill trying to lure him away from the joint.

And to hear his favourite Bellamy dressing down is something once more.

"I came back into pre-season a bit overweight after the World Cup," Asofa-Solomona told NRL.com.

"I was trying a vegan diet but I didn't do it right. I was trying all the sauces and trying to make that vegan food taste nice and I didn't realise that the sauces are the bad stuff for you.

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"After that break Craig brought me into the meeting room and there was a few people in there with us and he started going off his head.

"I was up to 127-128 kilos, I tend to play about 122-123, depending when I jump on the scales.

"Now I weigh in every morning, there's a few of us that do it but I think I'm the main culprit. I sometimes get more nervous about that than games sometimes, Craig's usually watching, he's always around doing some form of fitness.

"You'd be worried if he wasn't on your case, because you know where his intentions are and that he wants the best from you. It's all about how you take the criticism, I took that as a positive.

"For me the focus is my playing weight as much as anything. That's the key for me. He knows if my weight is going well, I play my best footy and everything falls into place mentally and physically."

Asofa-Solomona is a Wellington native from rugby mad New Zealand, with his hefty frame hard to miss even at the age of 15.

The Storm duly signed him up via their scholarship program, before New Zealand Rugby officials came in all guns blazing when he was ready to leave school and move to Melbourne in 2010.

Despite multiple approaches to his parents, who understandably would've liked him to stay close to home, Asofa-Solomona shunned the bigger offer tabled by Super Rugby's Hurricanes and the lure of a prestigious All Blacks jumper.

His loyalty stunned Storm insiders then, and is still spoken of fondly now ahead of the young buck's showdown with Roosters enforcers Jared Waerea-Hargreaves and Dylan Napa.

Asofa-Solomona's family have since made the move to Melbourne and the big man couldn't be happier with his lot in life.

"I love the Storm, I came over in 2010 and just fell in love with the culture and everything they stand for," he said.

"Rugby was interested for sure when I was young, it was a tussle between the Hurricanes and the Storm.

"In my heart I know I would've been comfortable in rugby but this was a serious test, moving to Melbourne, testing myself out and really trying to make myself a better player and person.

"The club has helped provide for my family and I do really just love the place here. It's a winning culture and the boys are great, I'm really enjoying life here. It's been the right decision to come here for sure and it's where I want to stay."