QUEBEC -- Quebec's interim auditor general believes the provincial government is being optimistic by promising a balanced budget within a few years.

Michel Samson issued a report Wednesday morning on an economic update brought down last November by Finance Minister Nicolas Marceau.

Samson said that there appears to be a one billion dollar gap to fill.

"If we can't increase the taxes you have no choice, you reduce the expenses, the expenditures or services rates are increased," he said.

Marceau's forecast called for deficits this year and next, but a balanced budget in 2015-2016.

Samson notes that Marceau's numbers assume certain uncertain future revenues, such as yet-to-be-approved electricity rate increases.

And he appears skeptical that the province can trim three percent from the health budget.

His comments come a day before Marceau delivers the 2014-15 budget, which is expected to include a deficit of $1.7 billion.

Marceau - who has promised just two percent spending increases for the next two years - wasn't backing down Wednesday.

"It confirms that we have been prudent that we have been responsible that our forecasts are reasonable," said Marceau. "We will not increase taxes and we will control spending."

The Liberals were warning that PQ spending would force the province to eventually make painful choices.

“I see at least two billion dollars of budget cuts in the next two or three years that's what is ahead of us and there's no growth to balance that,” said Liberal leader Philippe Couillard.

His fellow-opposition leader pointed out that there’s little idea of when the books will be balanced.

“Marceau is not giving us any indication about how he will eventually reach the break-even point,” said CAQ leader Francois Legault.