Despite bickering at city council and an ultimatum from the opposition, Montreal Mayor Valerie Plante says she has no plans to change the budget.

Plante is defending her tax increases, even as opposition party Ensemble Montreal threatened to vote against the proposed budget on Wednesday if amendments aren’t made.

“Montrealers know that you've broken your election promise to not increase taxes,” said opposition leader Lionel Perez at a city council meeting Monday.

“I have to tell you your outrage over the past week and today doesn't impress me,” Plante responded.

The opposition vowed to reject Plante's budget unless key changes are made, including eliminating the proposed water tax increase – the first hike since 2012.

“The increase in the water tax in actual numbers is $27.4 million,” said Perez.

That money is needed to repair and upgrade the city's aging infrastructure, said Plante – but Perez claims it's already in the city’s coffers.

“We have money in the capital works budget from last year that hasn't been spent. Over $100 million available that's available to be used,” he said.

The opposition also wants the city to set aside $10 million to compensate small businesses that suffer because of roadwork.

“With one hand, we're getting an increase in taxes for the non-residential sector, but at the same time there's no measure to protect those who are particularly going to be hurting because of city work,” said Alan DeSousa of Ensemble Montreal.

Two days after assuming office, Mayor Plante said she discovered a $358-million deficit left by the Coderre administration, reiterating at city council that’s why she had to raise taxes.

“You and the administration you were part of knew since last year we were headed for a wall,” she said to opposition council.

She cited as frivolous overspending by the Coderre administration the $3.4 million granite stumps on Mount Royal and the $24 million it cost to host the Formula E race.

“Seeing the disaster that you put Montrealers in, we decided to act responsibly and not throw money out the window,” she said.