Midfield blow for All Blacks

The All Blacks were dealt a cruel blow with the news that ace centre Conrad Smith has been ruled out for most of the Rugby Championship.

This means they will be without both midfielders that featured prominently in the June Test series whitewash of Ireland - when New Zealand won 42-10, 22-19 and 60-0.

With Sonny Bill Williams heading to Japan at the conclusion of the Super Rugby season, All Black coach Steve Hansen will have to find a new centre paring.

It was revealed on Wednesday that Smith underwent eye surgery, following the Hurricanes final game of the season just under a fortnight ago.

Hurricanes doctor Ian Murphy says Smith will be out for at least six weeks.

That means, at best, Smith may be available for the final two matches of the competition against Argentina and South Africa.

"Conrad had two procedures on his left eye for a retinal detachment last week, with the second last Friday," Murphy said.

"They both went well and he is now recovering at home.

"At this stage he is expected to be out of training for six weeks."

New Zealand start their campaign in the inaugural Rugby Championship - featuring Argentina for the first time - when they take on Australia in Sydney on August 18.

They face the Wallabies in the return Test in Auckland a week later, before hosting the Pumas (Wellington, September 8) and Springboks (Dunedin, September 15).

If all goes well Smith could be back when New Zealand head to Argentina where they play the Pumas in La Plata on September 29 and the Boks in Soweto on October 6.