Rocky Elsom was on Thursday dumped as captain of the Wallabies in a major shock and replaced by James Horwill for the World Cup in New Zealand starting next month.

In another surprise, veteran back Matt Giteau was left out of the 30-man squad announced by Australia coach Robbie Deans for the September 9 to October 23 tournament.

"We all felt it was in the best interests, both of Rocky and of the team, to relieve him of the extra duties, with James's recent experience making him the best option to take over in the role," Deans said.

Reds lock Horwill will become Australia's 77th Test captain when the Wallabies have their final hit-out before the World Cup in next week's Tri-Nations Test against the All Blacks in Brisbane.

Elsom was replaced after leading the Wallabies in their last 24 internationals, but retains his place in the squad as one of the options for lock.

"We all want the same thing now so it's all heading towards that," Elsom told reporters.

"I think it's important that everyone gets behind the captain, it can be a difficult job at times and you need everyone right behind you there."

Deans, who reinforced his reputation for making big selection calls, praised Elsom for his grace in losing the captaincy.

"Rocky's response was impressive and spontaneous and he simply said 'whatever was in the best interests of the team', so he remains an important person and important leader within the group," Deans said.

"It is well documented that Rocky came into the Test season off a limited background in terms of preparation, having missed all but 60 minutes of Super Rugby due to injury.

"As the incumbent captain, he warranted the opportunity to continue in the role but it has become clear that the additional responsibility has been a distraction that Rocky doesn't need."

Horwill said he was surprised and honoured to be handed the Wallabies captaincy after leading the Reds to this year's Super 15 southern hemisphere title.

"It's very much a surprise. It's something I feel very privileged to be given the opportunity to represent your country, and to be announced as captain is just another step and I'm greatly honoured for the opportunity," he said.

Giteau, who has 92 caps and was the Wallabies' highest-paid player and star playmaker until last year, missed out after hinting via his Twitter account on Wednesday that he would not be at the World Cup.

In Giteau's place, Deans selected Waratahs playmaker Berrick Barnes as the flyhalf back-up to Quade Cooper and Nick Phipps of the Melbourne Rebels as a third specialist scrum-half behind Will Genia and Luke Burgess.

Elsom is one of eight Wallabies who played at the 2007 tournament in France, where Australia bowed out in the quarterfinals.

The others from 2007 who are still in the squad are centre Adam Ashley-Cooper, Barnes, wing Drew Mitchell, hooker Stephen Moore, No.8 Wycliff Palu and locks Nathan Sharpe and Dan Vickerman.

Among the notables who missed out on World Cup selection were Mark Gerrard, Lachie Turner, Matt Hodgson and Dean Mumm.

All but four of the players who travelled to South Africa on the recent away leg of the Tri-Nations series have been included in the squad.

The players to miss selection from the South Africa trip are wing Lachie Turner, flank Matt Hodgson, lock Sitaleki Timani and prop Pekahou Cowan.

Players returning from injury into the squad are Mitchell, Palu, hooker Tatafu Polota-Nau and prop James Slipper.

While Barnes and Horne haven't yet played at an international level this year, both have worked their way back through club rugby, after coming off injury breaks.

All players returning from injury have been closely monitored in their work by the selectors using the latest technology to gauge fitness and general preparatory levels via their training output.

Squad members injured prior to, or during the New Zealand based tournament, can be replaced. All replacements are permanent however, which means covering short term injuries had to be factored into the make-up of the squad.

This is one of the reasons why three scrumhalf and hooker specialists had been selected.

“It was critical that we provided ourselves with cover for every conceivable eventuality in terms of injury,” Deans said.

“Looking at every scenario imaginable, and how that impacted on the squad, and our ability to still field a combination suited to the way we want to play, was a critical part of the selection process.

“We are fortunate to boast a lot of versatility amongst our backs especially but given the tournament regulations around replacements; additional cover at halfback and hooker was non-negotiable.”

Australia's 30-man squad charged with taking on the world in September and October will assemble in Brisbane on Sunday at Ballymore as the start of the preparation for Saturday week's Tri-Nations finale against the All Blacks, which will be played in front of a sell-out crowd.

A still to be determined number of players who are not required for the Tri-Nations finale, will instead feature for the Australian Barbarians as they tackle Canada at Skilled Park on the Gold Coast on Friday week.

The Canadians, who are grouped with the All Blacks, France, Tonga and Japan for the seven week tournament are stopping in Australia en-route to New Zealand.

The Australian Barbarians side, which will be coached by Wallabies coaching coordinator David Nucifora and fellow Wallabies coaching staff member Phil Blake, will be named on Sunday.

The Barbarians team will finalise its preparations for the Canadian match on the Gold Coast from next Wednesday.

As well as including members of the 30-man squad who are not required for the Tri-Nations finale, the Barbarians squad will be drawn from players who were previously involved with the Wallabies earlier in the year.

The players to have been involved in training with the Wallabies this year but to have missed selection for New Zealand are Mark Gerrard, Turner, Rod Davies, Luke Morahan, Matt Giteau, Dave Dennis, Hodgson, Dean Mumm, Timani, Ben Daley, Cowan and James Hanson.

Deans said this group would form the back up pool of players should the Wallabies require replacements during the seven week tournament.

“They've had the background with us. As such, they are the guys we will be looking to should further playing resources be needed at any stage,” he said.

“We will continue to monitor their progress at training, and their work in club games, as we have with the work of all of the players beyond our immediate match night squad through the season to date.”
 
Australia:

Forwards: Ben McCalman (Western Force), Radike Samo (Reds), Wycliff Palu (Waratahs), David Pocock (Western Force), Rocky Elsom (Brumbies), Scott Higginbotham (Reds), James Horwill (Reds, captain), Rob Simmons (Reds), Nathan Sharpe (Western Force), Dan Vickerman (Waratahs), Ben Alexander (Brumbies), Sekope Kepu (Waratahs), James Slipper (Reds), Salesi Ma'afu (Brumbies), Stephen Moore (Brumbies), Saia Faingaa (Reds), Tatafu Polota-Nau (Waratahs).

Backs: Kurtley Beale (Waratahs), James O'Connor (Western Force), Drew Mitchell (Waratahs), Digby Ioane (Reds), Adam Ashley-Cooper (Brumbies), Rob Horne (Waratahs), Pat McCabe (Brumbies), Anthony Faingaa (Reds), Berrick Barnes (Waratahs), Quade Cooper (Reds), Nick Phipps (Melbourne Rebels), Luke Burgess (Waratahs), Will Genia (Reds).