A CBC News investigation has revealed that drivers in Newfoundland and Labrador have a decent chance of not getting all the gas they've paid for.

Between January 2009 and May 2011, 962 gas pumps across the province were inspected. Tests showed that nine per cent of them were not measuring accurately.

As well, 56 per cent of the errors worked out in favour of the retailers.

"I think probably some attention is due to some of the pumps with regards to inspection purposes," said George Murphy, a consumer advocate who specializes in fuel prices.

Gas prices are regulated in Newfoundland and Labrador through provincial legislation, although the province relies on the federal agency Measurement Canada to keep an eye on pumps.

Inspections are currently not mandatory, although the federal government is now proposing inspections every two years.

Murphy said inspections should be much more frequent.

"Inspections as far as I'm concerned should be at least twice a year for every single pump, probably during the summer and during the winter — at least six months apart between inspections," Murphy said.

"It should be a mandatory thing."