Some Petro-Canada stations in the Prairies are running out of gasoline because of some unexpected repairs that have to be done at an Edmonton refinery.

Gasoline-producing units at the Edmonton refinery were supposed to keep running during a period of planned maintenance work, which began about a month ago.

But during routine inspections, Petro-Canada discovered repairs needed to be done and the gasoline units were taken out of service temporarily.

As a result, the refinery had to stop providing gasoline to some of its stations in Alberta, Manitoba and Saskatchewan, said Nicole Fisher, a spokeswoman for Suncor Energy Inc., the oil giant that owns the Petro-Canada stations and refineries.

Fisher could not say how many stations in the region are out of gas because officials are working to replenish supplies.

"So it might be that they've run out today, but they might get some gas tomorrow," she told CBC News on Thursday.

"We are bringing in fuel by rail and truck. We're sourcing it through third parties."

Fisher said the gas shortage could continue for about a month. There's no set timeline for when the refinery will start producing gasoline again, she added.

In the meantime, Suncor is making sure that the supply it has is being doled out in such a way that customers have alternative places to gas up if stations in their market are out of fuel, Fisher said.

With files from The Canadian Press