The return of several key players from injury has bolstered the New Zealand squad for their Tri-Nations campaign against Australia and South Africa.

Captain Richie McCaw (knee), Rodney So'oialo (neck) and Sitiveni Sivivatu (shoulder) will, as expected, all be involved for the first time this year after recovering from the injuries which kept them out of the drawn series with France and win against Italy.

Also recalled are wing Hosea Gear and forward Jason Eaton, who were both part of last year's end of season grand slam tour and the recent successful Junior All Blacks' Pacific Nations Cup campaign.

Eaton comes in for the injured Ali Williams, who will undergo surgery on Monday on his right Achilles and left shoulder. The 61-Test lock is out of rugby for the remainder of the year.

Gear replaces Lelia Masaga, who was a late call-up for the injured Rudi Wulf in the June Tests.

After three scratchy performances All Blacks coach Graham Henry admitted the team was under no illusions how challenging this year's Tri-Nations would be.

"It's going to be a huge contest right from the first Test. But this group of players has the resolve and the character to meet that challenge head on so we are expecting it to be another massive competition between the three top-ranked countries in world rugby," he said.

Liam Messam is the biggest casualty from those who were involved against France and Italy, with Masaga and another replacement player, George Whitelock, who scored against Italy on his debut, also not included.

New Zealand squad: Backs: Jimmy Cowan (Southland), Stephen Donald (Waikato), Hosea Gear (Wellington), Cory Jane (Wellington), Brendon Leonard (Waikato), Luke McAlister (North Harbour), Mils Muliaina (Waikato), Ma'a Nonu (Wellington), Joe Rokocoko (Blues), Sitiveni Sivivatu (Waikato), Conrad Smith (Wellington), Isaia Toeava (Auckland), Piri Weepu (Wellington).

Forwards: John Afoa (Auckland), Wyatt Crockett (Canterbury), Aled de Malmanche (Waikato), Jason Eaton (Taranaki), Bryn Evans (Hawke's Bay), Owen Franks (Canterbury), Andrew Hore (Taranaki), Jerome Kaino (Auckland), Tanerau Latimer (Bay of Plenty), Richie McCaw (Canterbury, captain), Keven Mealamu (Auckland), Kieran Read (Canterbury) Isaac Ross (Canterbury), Rodney So'oialo (Wellington), Brad Thorn (Canterbury), Neemia Tialata (Wellington), Tony Woodcock (North Harbour).