Sonny Bill Williams out of the Olympics

As a big blow to New Zealand's campaign in the Olympics rugby sevens, their star player Sonny Bill Williams has been ruled out of the tournament with an injury.

The 31-year-old suffered a "partial Achilles rupture" during New Zealand's opening game of the tournament where they faced a shocking defeat of 14-12 to Japan at Deodoro Stadium. The All Blacks centre was seen taken away by an ambulance shortly after he left the field in the second half.

The news was confirmed by the official Twitter handle of the New Zealand Olympic Team and he is expected to be on the sidelines for between six to nine months.

Sione Molia, who has been a travelling reserve will now replace Williams in the sevens squad in Rio.

New Zealand are scheduled to play Kenya and Great Britain in their remaining two encounters of the group to make amends for their defeat against Japan earlier in the day.