Premier David Alward is facing criticism from within his own party for his decision to raise taxes in the 2013-14 budget, breaking an election promise to hold the line.
Bill Carter, who was the Progressive Conservative youth president during the last campaign, says the party "ended up lying" to New Brunswickers.
"Personally, I think there's no excuse for that," Carter told CBC News.
He says he's saying publicly what many Tories are thinking privately.
"There's plenty that I talk to that, while not as vocal as I am, feel the same way," he said.
Carter believes the broken promise will make it more difficult for the Tories in the next campaign.
"I think we're going to have a lot of explaining to do," he said.
"How are we going to be trusted going forward to keep our promises? We had a contract with the people and we broke that contract."
Carter contends Alward has to show some leadership and demonstrate he's willing to get the deficit under control if he's going to ask New Brunswickers to pay more.
The deficit is now projected to grow to nearly $479 million in the upcoming fiscal year, up from the previously estimated $411 million this year.