Former All Black Carlos Spencer today confirmed he had signed for English club Northampton, but doesn't yet know if he has played his last game of rugby in New Zealand.

Spencer, sidelined from the Blues' Super 12 campaign for the past month because of injury, wants to turn out for the New Zealand Maori against the Lions in Hamilton on June 11 before heading to England.

But the mercurial first five-eighth has been told by coach Matt Te Pou he would also have to be available for the Maori against Fiji the previous weekend.

However, the trip to Suva clashes with ex-England skipper Martin Johnson's testimonial at Twickenham, where former All Blacks winger Jonah Lomu will make his comeback after a kidney transplant.

Spencer said he didn't know which fixture would take precedence.

"I couldn't answer that right now -- that's what I'll be thinking about over the next couple of days," he said.

"Jonah has been a great mate of mine for years -- we started at the Blues together -- and so what a game to be part of.

"And what better way to leave New Zealand than to put on a Maori jersey and play the Lions?"

Spencer, who had been contracted with the New Zealand and Auckland unions until the end of next year, was given an early release to take up a three-year deal with Northampton.

He will join two other New Zealanders, halfback Mark Robinson and fullback Bruce Reihana, at the Midlands club, which narrowly avoided relegation from the Premiership late last month.

Spencer said he was excited by his impending move, but also admitted that his demotion to the Blues' bench during the Super 12 had been a factor in his decision.

"I just felt it was the right time for a new challenge and I suppose being dropped from the Blues' starting line-up sort of helped to make that challenge," he said.

"I would be lying if I said it didn't. Sometimes you just need stuff like that to happen in your life to make you realise that it's time to move on."

Spencer, 29, played 35 tests for the All Blacks and 96 matches for the Blues, but in recent months has dropped down the pecking order for the No 10 jersey for both teams.

His last test was the 18-23 loss to Australia in Sydney in last year's Tri-Nations.

His move to England will end 14 seasons of first-class rugby in New Zealand.

Born in Levin, Spencer made his provincial debut as a 16-year-old for Horowhenua against Canterbury Country in 1992.

After starring for Horowhenua in a Ranfurly Shield challenge against Auckland the following year, he was lured north, and went on to play 94 matches for Auckland.

During his early years with both Auckland and the Blues, he played under present All Black coach Graham Henry.

Henry today described Spencer as the most influential player in Auckland rugby over the past seven or eight years, with skills that no one else in the game had.

"He's the sort of player that makes coaches look good," he said.

"There's many a time when I've been in the coaching role and 'Los' has been in the No 10 role and he's won games for Auckland that nobody else would have won."

Henry was disappointed that Spencer was heading overseas, but said he could understand why.

"He has been at the sharp end of the game in New Zealand for 12 years, which is a long time."

As well, Spencer's personal circumstances had changed. He had recently married and he and his wife had a young child.

He said the New Zealand Rugby Union was giving him an early release "as a thank you, really, for all the work he has done for NZ rugby, putting bums on seats for a long, long time".