Tyrel Lomax is expected to miss New Zealand's Rugby World Cup opener against France on 8 September after the All Blacks prop had to get 30 stitches for a gash in the leg from a stray boot during Friday's loss against South Africa at Twickenham.

The All Blacks suffered their biggest-ever defeat in the 35-7 reversal against the world champion Springboks with Lomax's injury adding to the concerns of coach Ian Foster ahead of the World Cup.

But while Lomax's involvement in the opener against the hosts is in doubt, the All Blacks' coach is expecting the 27-year-old to be available to play later in the tournament.

"Tyrel is very sore," Foster told reporters. "He's our worst injury.

"He's got 30 stitches, he got stitched by a surgeon last night at different depths. It's actually gone into the muscle.

"His leg will be in a brace for four or five days as we give that a chance to heal.

"Long term, he looks good. But that's put him into the 'unlikely' category in a fortnight."

The All Blacks will also be without forwards Brodie Retallick and Shannon Frizell for the meeting with the hosts, with the pair ruled out with knee and hamstring injuries, respectively.

However, Foster believes the players will return to the team earlier than initially expected.

"Both (are) running pretty well," said Foster. "Probably slightly ahead of schedule, but unlikely for France.

"But going well."

New Zealand share pool A with the French and Foster's team will also take on Italy, Uruguay and Namibia in the group phase as the All Blacks look to win a record fourth Webb Ellis Cup.