The loss of Christian Lealiifano, Bernard Foley and Quade Cooper to play overseas means locking in a new five-eighth will be a top priority for incoming Wallabies coach Dave Rennie.

The versatile Toomua had limited opportunities there under former Australia coach Michael Cheika, who mixed and matched his halves pairing throughout his tenure.

Toomua started at No.10 in Australia's World Cup pool game against Georgia but has only worn the jersey five times since making his debut against the All Blacks in 2013.

The 29-year-old said he wanted to stake an early claim on the jersey, with Australia's first internationals of the year against Ireland in July.

The Wallabies also host two Bledisloe Cup matches against New Zealand, with the first in Toomua's home town of Melbourne on August 8.

"My ambitions are the same as everyone, to get in that starting team, but with the changing of the guard there's a bit of unknown there," Toomua said.

"Like others you have dreams of being in a starting jersey and for me it would be that 10 jersey."

James O'Connor looms as another contender depending on where he plays in his return to Super Rugby with the Reds.

Toomua said he needed to form a strong combination with the anointed Melbourne Rebels halfback with a trio in the running to land the role after Will Genia's move to Japan.

Fiji international Frank Lomani, young Australian James Tuttle and South Africa-born veteran Ryan Louwrens are the No.9 hopefuls.

"I will have some competition there as well with Andrew Deegan, who did really well at the (Western) Force, so we've recruited well," Toomua said.

"There's some big holes with Will and Quade gone but I think with the young guys we've got coming through there's a recipe for success."

Toomua said he hadn't spoken to Rennie since the New Zealander's appointment last week.

However, he did recall that he hadn't had great experiences playing against Rennie-coached sides.

"I played against teams that he coached early on - was on the losing side in the Australian under 20s World Cup final and then the Super Rugby final, so hopefully he can help us win one," Toomua said.

Australian Associated Press