The win at the Stadium de Toulouse put New Zealand back on track in Pool A following their opening match defeat to host nation France.

It was a day to forget for the Namibians who were clearly out of their depth and powerless to prevent the All Blacks' 50th World Cup win.

The first score came following a pinpoint kick from flyhalf Damian McKenzie to Leicester Fainga'anuku who offloaded the ball to Cam Roigard for an easy finish.

McKenzie then added the first of eight conversions as he kicked 16 of New Zealand's points while crossing the whitewash for another 10.

Roigard was the only other player to bag a brace while Fainga'anuku, Anton Lienert-Brown, De Groot, Josh Papali'I, Siliva Havili, Caleb Clarke, and Rieko Ioane also scored tries.

The game was marred by an injury to Namibian centre Le Roux Malan who suffered what appeared to be a broken ankle.

In the 19th minute of the match, with Namibia trailing 12-3, Le Roux lost his footing when attempting a tackle on Beauden Barrett.

He quickly waved for medical attention as players from both sides looked away from his ankle which was facing the wrong way.

The match was stopped for around seven minutes as the 24-year-old received treatment before being escorted off the pitch on a buggy.

Following the restart, New Zealand mercilessly added to their total before De Groot was initially given a yellow card for a high tackle on Adrian Booysen in the 72nd minute.

His shoulder caught the head of Booysen in a lazy tackle that saw referee Luke Pearce's decision upgraded to a red card minutes later by off-pitch officials.

Former New Zealand winger Sir John Kirwan, who was a member of the 1887 World Cup-winning side, has predicted that De Groot will be banned for three weeks.

This would see him miss the remainder of the pool phase but be available for the beginning of the knock-out rounds.

New Zealand trail behind leaders France in Pool A and face Italy and Uruguay next on September 29 and October 5, respectively.