Conrad Smith may miss the All Blacks' opening Rugby Championship match after returning home to be with his pregnant wife.

Smith, who missed the final Test against England with a broken thumb, only joined his teammates on Thursday night before being summoned back to New Zealand. His wife had been due to give birth in the coming weeks, but it looks like his first child is going to come a few weeks early.

Highlanders centre Malakai Fekitoa, who made his debut in Smith's absence against England, will slot in if Smith is unable to make it back for the Test. All Blacks coach Steve Hansen has conceded that they are likely to be without Smith's services for the match against the Wallabies in Sydney.

'If it goes really well he could possibly be back, but we’re not holding our breath on that,' said Hansen.

The Crusaders' Ryan Crotty has been called into the squad as cover and will take Fekitoa's place on the bench if Smith remains in New Zealand.

Photo: Phil Walter/Getty Images