Staniforth, 19, continued his remarkable rise through the ranks when he captained the Australian under-20s team to a 34-5 win against Samoa on Wednesday.

The towering lock is also on the verge of signing a two-year deal with the ACT Brumbies , less than a month after he made his Super Rugby debut.

The Brumbies and Staniforth are in the final stages of negotiations to add the former Canberra Boys Grammar student to their roster for the 2015 and 2016 seasons.

Staniforth proved he could handle Super Rugby when he was thrust into a brutal initiation against the Queensland Reds earlier this month, after the Brumbies put him on a supplementary contract as injury cover.

The shy second-rower has been training with the Brumbies part-time for the past two years after graduating from the Australian schoolboy ranks.

In that period he's added nine kilograms and two centimetres to his frame as he strives to reach his Super Rugby goal.

Now at 113 kilograms and 198 centimetres, Staniforth's physical transformation is clear in his profile pictures from the past two years and he credits "mum's cooking" for his ability to bulk up.

"They [the Brumbies] told me I needed to put on weight but mum's cooking is probably the major factor in my weight gain," Staniforth said.

"The mixed grill is the favourite – steak, sausages, rissoles, a bit of gravy and mash only.

"I think I'm still growing, I like to think I've got a bit left in me and I think 115 kilograms is about the ideal weight but if I put on too much more I'll be a walker.

"I'm not really sure what's happening with Super Rugby, if I look too far ahead I get bogged down so I'm not looking at that."

Staniforth is the leading candidate to lead the Australian under-20s team to the world championships in June.

He has impressed his Brumbies teammates, earning high praise from skipper Ben Mowen and Wallabies star David Pocock.

Staniforth says his only focus is on securing selection in the under-20s team and helping Royals in their Canberra John I Dent Cup campaign.

But Brumbies and Wallabies prop Ben Alexander said Staniforth had unlimited potential.

"It all comes down to his attitude, the kid trains his absolute backside off," Alexander said.

"He's willing to learn, we give him some stick but that's because we love him and he fits right in.

"The Brumbies pride themselves on work ethic and he's got that in bucket loads. He's starting to get some pay for all that hard work, hopefully it gives him even more confidence he can mix it with the best. The sky's the limit for him."

Former Brumbies coach and World Cup-winning mentor Jake White added Staniforth to the ACT training squad last year.

"He's [Staniforth] another success story of how the club has moved on and on and on," White said.