New Zealand fullback Mils Muliaina has broken a bone in his foot in a practice match and could be out of action for eight weeks.

Muliaina will visit a specialist tomorrow to determine the extent of the injury but expects to be on the sidelines for between four and eight weeks depending on whether he needs a minor operation, a statement on the Waikato Chiefs website said.

Muliaina, a key member of the All Blacks backline who can play at fullback or centre, suffered the injury during a low-key practice match aimed at getting some of the country's World Cup players back in action.

New Zealand had banned their top 25 players from competing in the first half of the Super 14 season to reduce their chances of getting injured.

The select group were ordered to undergo physical conditioning but have been advised to resume playing this month to ensure they are fully match fit by the time the World Cup starts in France in September.