Quebec's bar and restaurant owners are upset about a retroactive tax announced by the provincial government.

The Parti Québécois announced a 25 per cent tax increase on alcohol served in bars and restaurants in Tuesday's budget. The new tax would apply retroactively to all the bottles businesses currently have in stock.

Bar and restaurant owners were required to take inventory of all their alcohol on Tuesday night, the same night that the new tax was announced.

Peter Sergakis owns several bars in Montreal. He said the government is being unfair.

"How can they pose a thing like that to us, without warning, without anything?" he said.

Sergakis said that for businesses with thousands of bottles in their wine cellars, it could be very expensive.

Finance Minister Nicolas Marceau said the retroactive tax is not unusual.

"We proceeded as we always did. There's nothing new," he said.

Small businesses will be affected by the new tax as well.

Chris Kassab, owner of a sushi restaurant in Westmount, estimates the retroactive tax will cost him about $40. But it's the principle that bothers him.

"Basically it makes me feel like I'm paying for the reduction in the student tuition that was given," he said.

Some bar owners have written to the government asking it to reconsider the tax.