New Zealand and Hawke's Bay lock Bryn Evans will be out of rugby for the foreseeable future due to a back injury that requires surgery.

The 24-year-old was forced to withdraw from the Magpies team for their Air New Zealand Cup match against Wellington last Saturday after suffering back pain while training.

All Blacks doctor Deb Robinson said scans had revealed a small disc prolapse which will require surgery and that it was too early to say how long he would be out of rugby.

"It's a case of him having his surgery and recovering from that first. Then he will go through his rehabilitation and we will take it from there," she said.

All Blacks coach Graham Henry said it was disappointing for Evans, who made his international debut this year coming off the bench in the two Tests against France in June.

"Bryn is an extremely skilful player and had been making great progress in the All Blacks environment and we will be supporting him as he goes through his rehabilitation," Henry said.

The All Blacks assemble for a one-day camp in Auckland on Wednesday with Henry due to name the 26-man squad for the Tri-Nations Test against Australia at the weekend.

Otago lock Tom Donnelly had already been called in as cover for Evans for the camp.