Nova Scotia drivers received a pleasant surprise Thursday morning when they discovered gas prices had plummeted about six cents a litre overnight.

The province’s price regulator invoked its rarely used interrupter clause late Wednesday, reducing the price dramatically and leaving many wondering what triggered the sudden drop.

"I know the margins have been higher then they should be,” says Wayne Pace, president of the Retail Gasoline Dealers Association. “When they are higher than they should be, then expect a fall."

Last Wednesday, gas in Halifax was selling for $1.43 per litre when the world markets went into flux.

On Thursday the price falls,” says Pace. “It falls again on Friday; falls again on Monday and on Tuesday."

Pace says that retail gas was selling too high last night, at an unfair rate and something had to be done.

"What it means is they are paying attention to what is going on in the market," says John MacDonell, Acting Minister of Economic and Rural Development.

For the time being, gas in Nova Scotia is cheaper than in New Brunswick by roughly three cents.

Pace says New Brunswick is likely next in line for a price drop.

“They are roughly four cents less for tax on a litre of gas then we are," says Pace. "I would say they'll have an adjustment, if not before next Wednesday, then by the next Wednesday.”

Pace says the price of diesel should see an adjustment at midnight, but that gas prices in Nova Scotia will likely stay the same, since the six cent drop came early.

With files from CTV Atlantic's Paul Hollingsworth