For those doubting the many youngsters in the Socceroos squad, James Holland has a simple message: if you're good enough, you're old enough.

Tasked with rebuilding the ageing Socceroos, coach Ange Postecoglou has selected a World Cup squad long on youth but short on experience.

More than half of the side will go into their clashes with footballing giants Spain, the Netherlands and Chile with fewer than 10 caps to their name.

At 25 and with 13 international appearances, Holland appears a seasoned veteran compared to some.

But the midfielder feels a young squad has its advantages.

"When you have a young team you have an ambitious and a hungry team so I think that can be the difference," he said on Sunday.

"I'm not sure if experience or age matters. If you're good enough, you're old enough."

Holland, who plays in the Austrian top flight with club Austria Vienna, competed in the UEFA Champions League (UCL) this season.

He faced the likes of newly crowned Spanish champions and UCL finalists Atletico Madrid, a side boasting several Spanish internationals who the Socceroos will also encounter in their final World Cup group match in Curitiba on June 23.

But Holland is still hoping to reach greater heights and is more than aware of the opportunity a World Cup presents to put himself in the the "shop window".

"I hope there's a long way to go. That's that plan. You always want to improve," he said.

"In football your whole world can change in 24 hours and I think the World Cup is an opportunity for everyone."

The Socceroos endured another gruelling training session at their base in Vitoria on Sunday.

Defender Ivan Franjic was missing for a second day, with concerns over playmaker Tom Rogic and striker Josh Kennedy who were also rested.

Right-back Franjic injured his knee in the farewell match against South Africa in Sydney on Monday when he collided with teammate Alex Wilkinson.

Rogic, who has barely played for months because of a groin injury, and Kennedy, who has had ongoing back concerns, were both rested on Sunday.

FFA officials played down concerns saying it was simply part of managing their training.

Postecoglou is expected to name his final 23-man squad on Wednesday. -AAP