AAP

One is currently playing for the Wallabies and has been a mainstay at the Western Force since 2010. The other is a former All Black who has been lured to the Perth-based franchise as their marquee international player.

Welcome to the selection headache facing new Force coach Michael Foley, who must choose between 33-year-old Brett Sheehan and 26-year-old Kiwi Alby Mathewson for the starting halfback role.

The Force have completely revamped their backline since their doomed 2012 campaign, when they only narrowly avoided the wooden spoon.

Former Cheetahs five-eighth Sias Ebersohn, Junior Rasolea, Sam Norton-Knight, Ed Stubbs, Jayden Hayward and Chris Tuatara-Morrison are among the new arrivals, along with Mathewson.

But the most intriguing question is who out of Sheehan and Mathewson will get the nod at halfback.

Foley doesn't yet have the answer, but it's a question he'll ponder heavily over the next few months as he runs his charges through a typically gruelling pre-season campaign.

"It definitely will be a battle. All good nines have that type of personality anyway," Foley said on Monday.

"We are extremely lucky to have two international nines. Nine is the position that touches the ball more than any other.

"Temperament at nine and 10 is critical.

"I can think of any number of nines and 10s that have a complete skill set and physically they're good.

"But when the pressure really comes on, their decision making fails them.

"So temperament will be very important - making the right decision at the key times."

Whichever way Foley goes, he will be safe in the knowledge a quality No.9 will be running the play for the Force.

Mathewson notched four Tests for the All Blacks in 2010 and spent the previous three seasons with the Blues.

Sheehan's international career was revived during the recent Rugby Championship following a raft of injuries to Australia's scrumhalf stocks.

"Both of them have a nice running game around the edge of the ruck and they're tough, so they're not frightened to get close to big forwards and play our guys through those holes," Foley said.

"And both of them have good a good pass.

"Besides the temperament, we're looking for them to get to the ball quickly and do something with it."

The arrival on Monday of former Highlanders and Hurricanes centre Hayward as the Force's second overseas development player completed the club's 30-man roster.