Armed with ex-Wallabies Israel Folau and Adam Coleman, and five former All Blacks, Tonga coach Toutai Kefu says the “massive X-factor” in his Rugby World Cup squad can help the Pacific Island nation mount a challenge to pool rivals Ireland and South Africa.

And they will begin their World Cup preparations with a clash against Australia A next month in Tonga – a clash that is likely to feature Wallabies squad members.

Kefu, the former Wallabies No.8 who won a World Cup in 1999, named a preliminary 35-man World Cup squad on Wednesday and with an array of star names.

Under changes to World Rugby’s rules in 2021, a player can now switch eligibility to a second country of their heritage, following a three-year stand-down. A raft of players stuck their hands up to play for world No.15 Tonga.

Among those named by Kefu were ex-Wallabies Folau (who made his debut for Tonga last year), Lopeti Timani and Coleman, who represented the Wallabies at the 2019 Rugby World Cup. Former All Blacks Charles Piutau, Vaea Fifita, Malakai Fekitoa, George Moala and Augustine Pulu are also in the Tonga squad.

Australia fans would also remember former Super Rugby stars Solomone Kata, Steve Mafi, David Lolohea, Feao Fotuaika, Sam Lousi and Afusipa Taumoepeau.

Kefu said it was the best Tonga squad ever assembled.

“This is obviously a different class of side compared to teams we have had in the past, and what it enables us to do, it provides us with some massive X-factor,” Kefu said.

“It was pretty easy [to put together], to tell you the truth. They were all pretty keen to play for Tonga. Most of these boys, like Piutau and Fekitoa, they all grew up in Tonga, until the age of 14 and 15, and then they moved overseas, so they were all really keen.”

Coleman – who played 38 Tests for Australia – has Tongan heritage from his father, Pau’u Afeaki, who captained Tonga but passed away when Coleman was 12.

“He is a proud Tongan and he holidays in Tonga quite regularly in the off-season,” Kefu said.

“He had some issues obviously with his club side [London Irish] folding recently, so that’s been a bit of a distraction but, yeah, most of the conversations we have had have revolved around him being really passionate to represent that side of his family.”

Folau suffered a hamstring injury on debut for Tonga last year against Fiji, but after playing in Japan and for the World XV against the Barbarians last month, the former Wallabies fullback is “very excited” about playing at his second World Cup, said Kefu.

Tonga have Ireland, South Africa and Scotland in their pool, so progressing to the quarter-finals will be tough. But Kefu believes the team can become the giant killers of this World Cup, and none of the trio should feel safe.

“It certainly can be done,” he said. “I am a person that believes the world is your oyster. I believe in thinking positively, and we have the cattle now. And with the level of player comes a higher level of expectations.”

The Tonga squad will gather for a camp at the end of the month ahead of a six-game warm-up, including the Pacific Nations Cup, two Tests against Canada and a clash with Australia A in Tonga.

The game will double as a 50-year anniversary of Tonga’s famous victory over the Wallabies in 1973, Kefu said.

Rugby Australia says details are still be finalised, but it is expected to be on July 14, a day before the Wallabies’ clash with Argentina in Sydney. Some Wallabies squad members are expected to fly over and join the Australia A squad.

Brumbies captain Allan Alaalatoa will not make his return from a calf injury in the Brumbies’ semi-final clash against the Chiefs on Saturday after the Wallabies disagreed with an early comeback for the tighthead prop.

Alaalatoa strained his calf three weeks ago in the Brumbies’ round 14 loss to the Chiefs, but after missing the quarter-final, the experienced prop returned to team training in Canberra this week.

According to informed sources, Brumbies and Wallabies medical staff had initially agreed Alaalatoa would need four weeks on the sidelines, under the protocol for handling the return to play timelines of nationally contracted players with injury.

But after progressing well, the ACT club was optimistic Alaalatoa could make a return in the semi-final in Hamilton on Saturday, against Super Rugby Pacific’s minor premiers the Chiefs.

But the possibility of a comeback was stopped after discussions between the Brumbies and the Wallabies camp, who considered it too early, and too big a risk with only … days before Eddie Jones’ side plays its first Test of the winter against South Africa in Pretoria.

With Taniela Tupou not yet ready to return from a torn Achilles’ tendon, the Wallabies are extra cautious about ensuring Alaalatoa is available and fully fit for the Springboks’ clash, and the subsequent Rugby Championship campaign, with games against Argentina and New Zealand to follow.

The Wallabies’ depth at tight-head is comparatively light, with Pone Famaumisili and uncapped Brumbies rookie Rhys Van Nek the other tight-heads named in Eddie Jones’ first squad in April. Tom Robertson was also in the squad but has since been ruled out for the year after injuring his ACL for the Force.

After the Brumbies downed the Hurricanes in a thrilling quarter-final at the weekend, Brumbies coach Stephen Larkham said he expected Corey Toole to return from an ankle injury, but Alaalatoa was unlikely.

“Allan’s is a little bit more serious than [Toole’s injury],” Larkham said. “He’s improving everyday, but I don’t think it’s going to be there for him. There’s a bit of work to be done there.”

Playing down early fears he’d be ruled out of the Pretoria Test, Alaalatoa said two weeks ago he’d been encouraged by the progress of his calf injury but would take a cautious approach to returning to the field.

“Soft-tissue injuries are all dependent … on the individual and how they heal, and I’m already ahead of where I’m meant to be,” he said.

“It’s more just being in the moment and being present, but also making sure that I’m not making stupid decisions. There’s a bit of honesty towards that and I’m making sure when I do those tests I’m honest with how I feel, so I’m not a liability to the team.”