Boom Reds flanker Liam Gill's cherished appointment as Australia's captain for the under-20 World Cup looks set to stop him becoming the first teenaged Wallabies forward in 39 years.

Not since former Wallabies and Queensland skipper Mark Loane made his Test debut as an 18-year-old in 1973 has Australia fielded a teenager in their pack.

But the in-form Gill was well on track to gain his first Test cap, probably as David Pocock's No.7 back-up, against Scotland at 19 and 362 days until being named as skipper of a 28-man Australian U20 squad by coach David Nucifora on Wednesday.

The tournament kicks off in South Africa just before the Scotland Test in Newcastle on June 5 and Wallabies coach Robbie Deans has in the past shown he'd rather leave young guns to represent the national U20s for their development.

It seems only an injury to Test vice-captain Pocock is likely to see Gill, who was called back from last year's Junior World Cup at the 11th hour due to a Reds injury crisis, remain in Australia.

But it wasn't anything that would dampen his mood on Wednesday when named as one of four contracted Reds along with Nick Frisby, Chris Sautia and Ulupano Seuteni.

"I'm thrilled to be given another opportunity at the Junior World Championships - it's a great tournament to play in," Gill said.

"I'm sure all the guys can't wait to get to South Africa to test themselves against the best on offer from the other nations."

The instinctive ball scavenger's 2012 form has him rivalling Western Force stalwart Matt Hodgson and rising Brumbies star Michael Hooper as Pocock's understudy at openside flanker.

Gill, set to go head-to-head with All Blacks skipper Richie McCaw in Sunday's Super Rugby final rematch in Christchurch, is already following in the footsteps of some of Australia's modern-day back-row greats.

Pocock was 20 when he made his Test debut against the All Blacks in Deans' first season in charge in 2008 while predecessor George Smith was also 20 when he played his first Test against France in 2000.

"I'm not surprised," Reds coach Ewen McKenzie told AAP.

"We've been managing his exposure but, gradually more and more, he's showing his quality at this level.

"Only a young guy at 19, he's got great instincts and he's very talented."

Australia are top seeds in pool C at the world championships, taking on France, Argentina and Scotland.