Dan Carter's World Cup warning - The area the All Blacks need to fix

All Blacks great Dan Carter has sounded a warning ahead of next year's Rugby World Cup.

While the tournament is still 15 months away, Carter is adamant now is the time the All Blacks have to settle on their best lineup.

The former first-five says the All Blacks have struggled to build combinations recently, and argues they could be in trouble if they don't find their best team shortly.

"This is the time teams need to start putting combinations and giving reassurance to players to really start establishing," Carter told the Daily Telegraph.

"And you need to know the players that are being backed around you as well, because you've got to build combinations and that's something the All Blacks haven't been able to do for whatever reason over the past couple of years.

"It's normal post World Cup to give guys a go, but there comes a time when you need to establish, you can't be doing that next year at the World Cup, you need to do it this year."

Carter predicts the three-test series against Ireland, starting this week, will be an excellent gauge of how the All Blacks are tracking in their quest for a fourth World Cup title.

"Ireland completely outplayed the All Blacks last November, their three-match series in New Zealand is going to be great for the All Blacks to see where they are and what they need to improve."

Carter thinks the northern hemisphere teams will ensure the Cup is competitive in France next year.

"It's exciting to see the growth of Irish rugby in particular. England will build, this July series will be huge with England playing in Australia, that will be a challenge to see where England are at, they've had a bit of success in Australia.

"There's half a dozen teams that could be there in the World Cup final."

Fellow All Blacks legend Richie McCaw agrees with Carter, predicting there will be competitive clashes that will make life tough for the All Blacks.

"There's going to be a handful of teams that are always going to be thereabouts. From New Zealand's perspective, to be playing France in the opening game, they're two teams that could easily be in the final," McCaw told the Daily Telegraph, recalling the 2011 World Cup where France and New Zealand clashed in the final after also playing in pool play.

"They'll end up on either side of the draw, it could easily be like 2011, so it's an intriguing start.

"You can probably name four or six of the teams that will be in the quarters, the others now have the ability to cause issues to some of those teams."

The two-time Cup-winning captain says being able to back up dominant performances – as well as a little luck – is what wins World Cups.

"Sometimes there's a bit of luck, there's a whole lot that goes into it, not getting injuries.

"To play three knockout games in a row, they're all big games and you've got to be on the job.

"We saw that against England last time in the [2019] semifinal, they played a hell of a game in the semifinal and couldn't quite get to that same level [against South Africa in the final].

"And in 2011 we were like that against the Wallabies, we had an amazing performance in the semi, and we couldn't get back to that. It didn't cost us the game but it certainly made it tough."