Five of them were hit by gunfire and two of them have been seriously wounded and are in hospital.
The police officers were attacked on Sunday when they tried to clear the road linking Noumea and Mont-Dore after protesters had blocked it with burning cars and tyres.
The road has been closed since Saturday when police fatally shot the driver of a stolen vehicle who was reportedly stopped but then backed up to try to run over a police officer.
Reports said there were several people in the stolen vehicle and one of them has been arrested.
The man who was shot dead has been named as 23-year-old William Decoire from St Louis who had 19 convictions for robberies and who had been on the run since June last year.
The government is in talks with the people of St Louis to calm the situation.
Gymnasiums have been opened to accommodate people stuck on either side of the roadblock, and a naval vessel is to provide basic transport.
The French High Commissioner, who is responsible for security and who was en route to Paris, has decided to return to Noumea.
- RNZI