Carter, 26, who has played 46 Tests for the All Blacks since 2003, is keen to re-sign with the NZRU until the end of 2011 and said representing his country remained his over-riding priority.
"For that reason I have decided to re-sign with the New Zealand Rugby Union, ideally to 2011.
"If selected I certainly want to be a part of a successful All Blacks World Cup campaign," he said.
Carter is in negotiations with two French clubs, one of which is Toulon who are coached by his former All Blacks captain Tana Umaga and who have offered him a reported NZ$1.4 million.
"I have made no final decision about the sabbatical and where I will be, but it should be resolved in the next fortnight or so."
The NZRU have been keen to find a way to slow the steady drain of players overseas and see the sabbatical option, dubbed the "Carter Clause", as a way of tying players to New Zealand while allowing them the chance to play abroad and earn big money while experiencing a different lifestyle and culture.
New Zealand players playing abroad are not eligible for selection to the All Blacks.