England's elite rugby director Rob Andrew believes New Zealand have been short-sighted in allowing star players Dan Carter and Richie McCaw the opportunity to take lucrative sabbaticals.

Carter is in the process of negotiating a six-month stint in Europe next season - Toulon being the likely destination - and McCaw's new contract with the New Zealand Rugby Union now allows him to follow suit.

Crucially, the sabbatical option means Carter will remain eligible to play on New Zealand's November Grand Slam tour when NZRFU policy is not to select players who are based outside of New Zealand.

McCaw was quick to stress at a hastily-arranged press conference today, where it was announced he had signed a new deal through to the 2011 World Cup, he has no immediate intention of playing abroad.

And NZRFU chief executive Steve Tew presented the announcement of McCaw's new deal as a victory for the power of the All Blacks jersey over the lure of big European money.

However, New Zealand have already lost key figures like Carl Hayman, Luke McAlister and Doug Howlett to Europe and, with the sport at a low ebb following the All Blacks' World Cup failure, they could scarcely afford for Carter and McCaw to follow suit.

But Andrew believes the NZRFU decision to allow the star names such flexibility could well backfire on the All Blacks.

Andrew said: "This is another shift in professional rugby and another example of how the game is evolving and developing.

"I do think it potentially creates as many problems for the southern hemisphere countries as it does for the northern hemisphere.

"How do they manage this sabbatical? Does it mean the player plays 18 months full-on rugby, which is the likely scenario.

"Or does Carter miss half the 2009 Tri-Nations because he is knackered from playing for six months in Europe?

"It is fraught with difficulties. It might be seen as a short-term solution to hang on to Carter and McCaw. But I don't think it is a long-term solution because inevitably the players will suffer.

"Look at the South Africa guys. Is Butch James playing right through the Tri-Nations and then coming back to Bath?

"Where is his 10-week off-season? You can't sustain that."

Tew accepted New Zealand are struggling to compete in a strong marketplace but he hopes the decisions made by Carter and McCaw to remain predominantly based at home will send out the right signals to other players considering a move abroad.

"We're delighted for him to make a commitment to New Zealand rugby and the All Blacks and on top of the decision Dan is working through, we think it's a pretty good signal for the future for us," said Tew.

"We're obviously working hard to retain as much of our talent as we can and we've made no secret of the fact we find the challenge is now, particularly with the economies of the French and English rugby environment, difficult for us.

"We have maintained though that there are some things that are special and unique about New Zealand rugby and I think Richie's saying for him at least they are enough to keep him here and inspire and challenge him."

Andrew was matter-of-fact about the potential impact on the Guinness Premiership clubs if big-name stars from the Tri-Nations became available on short-term contracts.

South Africa's World Cup-winning lock Victor Matfield has just returned home from an unsuccessful stint with Toulon.

"We are in a professional game," said Andrew.

"The market will decide whether somebody wants Carter for six months or if they wanted Victor Matfield for six months, and they did.

"Providing we keep the numbers where they have been for most of the professional game, which is 65% English qualified in the Premiership, then we have to accept that through European law there are difficulties in restricting the numbers of foreign players."

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