Fiji flyhalf Caleb Muntz has been ruled out of the Rugby World Cup due to injury.

The 23-year-old looked set to start Sunday's Pool C clash against Wales in Bordeaux, but he suffered a knee injury during training on Monday and will miss the tournament.

Muntz played a key role in Fiji's World Cup warm-up victory over England at Twickenham, kicking 15 points from three conversions and three penalties.

"Caleb sustained a knee injury in a non-contact session and is out of the Rugby World Cup," Fiji head coach Simon Raiwalui said on Fiji Rugby's website.

"It's most devastating for us as a group and for Caleb. He has worked so hard for the past two years."

Raiwalui added replacement options for Muntz were being considered and will make a decision in the next couple of days.

Teti Tela is the only other specialist flyhalf in the squad.

The Pacific islanders are in Pool C at the World Cup and open their campaign against Wales in Bordeaux on Sunday.

They also face Australia, Georgia and Portugal in their group.