Mitchell has opted to stay in New Zealand

Mitchell signed a three-year contract to take charge of Waikato's National Provincial Championship side.

The New Zealand Rugby Union also publicly rejected rumours that Mitchell had an affair with his personal assistant at the World Cup.

A statement read: "The NZRU regrets that John has been subjected to unsubstantiated and hurtful gossip."

NZRU chief executive Chris Moller said a thorough review had been conducted of New Zealand's failed World Cup campaign which found no evidence of "inappropriate behaviour" by players or management.

Mitchell's assistant Bridget Hickman was sent home from the World Cup, leading to rumours that she had had an affair with Mitchell, who is married with two children.

"[The rumours] are just rubbish and why should I put up with that legend when it's not true," said Mitchell.

John is an experienced international coach and we are delighted he has agreed to remain in New Zealand NZRU's Chris Moller

"I've been very explicit in that area in the last few weeks because [the rumours] are not true and it was very important I express myself in that way."

Mitchell said the union's statement not only cleared his name but gave him credit for his achievements over two years as All Blacks coach.

That recognition was reinforced by the New Zealand union's decision to contract Mitchell for two years to a technical coaching role.

"John is an experienced international coach and we are delighted he has agreed to remain in New Zealand," Moller said.

"He delivered an outstanding on-field performance with a young and exciting All Blacks team, impacted only by the disappointing World Cup semi-final loss to Australia."

Moller said Mitchell's coaching record was the third best in the 100-year history of All Blacks rugby and the best in the professional era.

He coached the All Blacks to 22 wins, four losses and a draw in 27 Tests.