The All Blacks have been rocked by twin injuries on the eve of their first match at the rugby World Cup, raising the early spectre of a replacement player being called to France.

Centre Conrad Smith and reserve lock/loose forward Reuben Thorne both failed fitness tests on hamstring strains today and were ruled out of the pool C test against Italy at Stade Velodrome here tonight (NZ time).

Smith's place is taken by Mils Muliaina, who shifts from fullback. Replacing Muliaina at the back is Leon MacDonald, with Isaia Toeava taking MacDonald's spot on the reserve bench.

Thorne makes way on the bench for Chris Masoe.

"It's a frustration for the players, they're really upset about it," coach Graham Henry said.

"We've just got to bite the bullet and get on with it.

"We're hopeful that they'll come right, and reasonably quickly. But it's that sort of injury that it's hard to judge what the time scale will be."

Smith's hamstring tightened late at training yesterday, continuing his wretched year with injury. The same injury has sidelined him through almost all of New Zealand's test campaigns this year, with just seven minutes off the reserve bench against the Springboks in Christchurch his lot.

Henry said the multi-skilled Muliaina was preferred in the No 13 jersey over Isaia Toeava as he had trained with the starting team all week.

Thorne, who twinged his hamstring two days earlier than Smith, involved himself in training yesterday but the medical staff deemed him a risk to play.

His absence leaves the All Blacks locking stocks thin, with Keith Robinson already ruled out with a calf injury.

Specialists Chris Jack and Ali Williams will start and their backup will be blockbusting loose forward Sione Lauaki.

Henry said Lauaki had slotted in at lock during the All Blacks' trial matches in Christchurch and Auckland last month.

Robinson was also confirmed today as a non-starter for the second pool game against Portugal in Lyon next week, leaving Henry crossing his fingers the tough lock can be ready in time for the third pool game against Scotland at Edinburgh on September 23.

"Hopefully that will be a possibility but we don't know yet," he said.

If Robinson or Thorne continue to struggle or if Jack or Williams sustain an injury, the All Blacks are sure to call over a replacement. The question is when.

"We've just got to be patient, have a contingency plan up our sleeve in case it doesn't come right and get on with it," Henry said.

"We'll see how long this is going to take. At some stage we're going to have to make a decision."

Their options were likely to be discussed before kickoff tonight.

Henry rejected reports suggesting that Auckland lock Troy Flavell was on standby.

Auckland coach Pat Lam insinuated Flavell had been rested from this weekend's Air NZ Cup game against Northland with the possibility that an All Blacks call up could be looming.

"It's never been discussed with anybody who's on standby as far as replacements are concerned. So I don't know where that's come from," Henry said.

"He's one of the players we'd look at if we needed a replacement lock."

All Blacks captain Richie McCaw at least removed himself today from the casualty ward, saying the virus that kept him from training yesterday had improved considerably.

He said it would be wrong to attribute the injuries to New Zealand's lack of playing time since their last test seven weeks ago.

"I don't think hamstrings are too much to do with that. It's more bad luck."

McCaw didn't think his side would be thrown by the changes.

The biggest hurdle would be overcoming an Italian side who were unlikely to lie down.

"They're going to be a good challenge, especially up front," he said.

"We'll have to make sure we have good set piece ball ... that's where a big part of the game will be sorted out tomorrow.

"If we allow them to disrupt it and get the ball themselves, it's going to be a long day."

Italy coach Pierre Berbezier today continued his theme of talking up the New Zealanders.

"The All Blacks are always the All Blacks," he said.

"The most important thing is the spirit they have and nowadays it is the same as when I was a player. When I played them they were always a big team and it was always a big game.

"Tomorrow is going to be a beautiful match."

MacDonald's introduction gives the All Blacks 649 combined caps in their starting lineup, nearly 50 more than the previous most experienced test lineup.

All Blacks team:

New Zealand: Leon MacDonald, Doug Howlett, Mils Muliaina, Luke McAlister, Sitiveni Sivivatu, Daniel Carter, Byron Kelleher, Rodney So'oialo, Richie McCaw, Jerry Collins, Ali Williams, Chris Jack, Carl Hayman, Keven Mealamu, Tony Woodcock. Reserves: Anton Oliver, Neemia Tialata, Chris Masoe, Sione Lauaki, Brendon Leonard, Aaron Mauger, Isaia Toeava