Chiefs scrumhalf Augustine Pulu has been ruled out of the Super Rugby's Finals Series due to a broken arm.

Pulu, who represented the All Blacks in two Tests on their 2014 end-of-year tour, sustained the injury after coming on as a replacement in the Chiefs' 21-13 defeat to the Hurricanes in New Plymouth on Saturday.

"Pulu underwent surgery earlier today to insert a plate," the Chiefs revealed via a press release on Sunday.

"The expected return to play time is 8-10 weeks."

The 25-year-old's injury is a major setback for the Hamilton-based franchise ahead of their Finals Series clash with the Highlanders in Dunedin on Saturday.

The Chiefs have also been without another All Black scrumhalf, Tawera Kerr-Barlow, since the start of the season after he tore ligaments in his knee in a Rugby Championship Test against the Springboks at Ellis Park in Johannesburg last October.