TORONTO -- Ontario's New Democrats started paving the way Thursday towards triggering a spring election by suggesting they won't support the minority Liberal government's budget for a third consecutive year.

The NDP accused the Liberals of moving too slowly on a promise from last year's budget to cut auto insurance rates an average of 15 per cent over two years, and said the government was not keeping its word.

"The fact that commitments made are not being followed through on, I think that's something we have to take into consideration when we look at any upcoming budget," warned NDP consumer critic Jagmeet Singh. "There's no way we can't look at the fact that promises made are not being followed through on."

The province's insurance regulator, the Financial Services Commission of Ontario, approved premium decreases for this quarter averaging 3.9 per cent, which the Liberals said means they are on track for a 15 per cent reduction by August 2015. The government said rates are down a total average of 4.66 per cent since last August.

But Singh called it "unacceptable" that most of the rate decreases won't take effect for several months, after many drivers renew their policies for another year.

"The Liberal government is telling drivers to wait before they see a reduction when we know that they moved so quickly to reduce the costs and increase the profits of insurance companies," he said.

"It's another example of a flashy headline grab, but when you look at the finer details you see the realities that these reductions aren't actually happening in this quarter."

Insurance reforms implemented in 2010 reduced benefits in many cases, helping lower costs for companies and leading to record profits, and some of the money should be returned to drivers in the form of lower rates, added Singh.

"Experts have testified that the industry enjoyed a $1.6 billion after-tax profit in 2012, but drivers are still waiting for relief, and some have seen steep hikes," he said.

The New Democrats forced the Liberals to make major concessions in exchange for supporting the past two budgets, including a new tax on high income earners, money for a youths jobs strategy and creation of a financial accountability office. Getting results for people that make life more affordable remains the NDP's goal, said Singh.

"Our priorities are not about going to an election or not going to an election," he said. "Our priorities are about how can we make this a better province for the people of Ontario, how can we advance their concerns in the best way possible."

The Progressive Conservatives want an election as soon as possible, so the Liberals know they again need NDP support if their budget is to pass and avoid a spring campaign