All Blacks captain Richie McCaw signed a four-year deal to stay in New Zealand after this year's Rugby World Cup, but retained an option to play club rugby overseas.

Hailed as the most influential player in world rugby by All Blacks' coach Graham Henry, the talismanic skipper joined star fly-half Dan Carter in re-committing to the national side and Super Rugby team the Crusaders.

Unlike Carter, who said he agonised over the decision and came close to walking out on the All Blacks - who do not consider overseas-based players for selection - McCaw said staying in New Zealand was always his preferred option.

"I've always said that as long as I am enjoying playing footy in New Zealand then I will stay, and the fact is I still am, so I'm pleased to confirm that I have re-signed with the New Zealand Rugby Union for four more years," he said.

"I still have the hunger and desire to continue to play for the All Blacks and the Crusaders and there are still things I want to achieve as a player."

The deal means McCaw, 30, will have played his entire career in New Zealand, even though the 94-Test veteran and three-time IRB player of the year could command a huge pay packet from rich overseas clubs.

Like Carter, he has a "sabbatical" clause built into his latest contract, allowing him to play overseas if the lure of the riches on offer outside New Zealand becomes too tempting.

With McCaw's signing and last week's retention of Carter, the NZRU has managed to keep its top two players, easing fears of an exodus after the World Cup, which will be played in New Zealand from September 9 to October 23.

NZRU chief executive Steve Tew said McCaw's and Carter's on-field chemistry was a major factor behind the All Blacks' success, noting the team had won 88 per cent of the 51 Tests the pair have played together.

"To have both players continuing with us for the next four years is fantastic news," he said.

While Henry praised McCaw's leadership abilities and "immense" on-field impact, local media questioned the wisdom of keeping the player dubbed "Captain Fantastic" for another four years.

Fairfax Media columnist Duncan Johnstone described the contract as a "gamble", given McCaw's age and injury record, questioning whether he would still be operating at his peak at the 2015 World Cup in England.

With McCaw's and Carter's deals secured, the NZRU's attention is likely to move to Sonny Bill Williams, who Crusaders' coach Todd Blackadder said this week was as just as important to the All Blacks as the veteran pair.

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