QUEBEC - Prime Minister Stephen Harper promises to remain neutral -- up to a point -- in the upcoming Quebec election, the leader of the province's third-largest party said Tuesday.

Mario Dumont, leader of the Action democratique du Quebec, said the prime minister personally assured him in a meeting Tuesday that he would not play favourites between the governing Liberals and the ADQ.

That guaranteed neutrality does not extend to the Parti Quebecois, he quickly added.

"He told me privately what's been said publicly: the Conservative government will not support a political party in the next election,'' Dumont told a news conference on Parliament Hill after meeting with Harper.

"It's normal for him not to hope for the election of a Parti Quebecois government  that wants to hold a referendum -- that's only obvious. But for the rest, I don't think the prime minister of Canada and government of Canada will interfere with the (provincial) election.''

Dumont brushed off the suggestion that Harper actively assisted Liberal Premier Jean Charest's re-election drive this week when they appeared together at a splashy announcement.

Charest's Liberals are expected to base their entire campaign around their ability to work co-operatively with Ottawa. Harper bolstered that strategy this week by going to Quebec to announce a $1.5 billion environmental fund for the provinces -- $350 million of which will go to Quebec.

The prime minister is also expected to include large provincial transfers in the federal budget slated for March 20, just six days before the anticipated provincial election date.

But Dumont brushed aside the idea that Harper's moves will help Charest. He said the election campaign is not about getting money from Ottawa, but about who has the best plan to handle that money.

"I'm not waiting for Stephen Harper, for the Conservative party, to come and win my election for me in Quebec,'' he said.

Dumont's party runs a distant third behind his two more established rivals, but the ADQ has seen its support grow in recent weeks and is particularly strong in specific pockets of the province.

The PQ, after having been in first place for almost the entirety of the last four years, has fallen behind the Liberals in popular support. Support for sovereignty has remained relatively high, at well over 40 per cent.

Harper did not join Dumont for his news conference after what the Prime Minister's Office described as a "private meeting'' between the two.

Dumont said Harper's recent promises to take action against climate change have eliminated one possible irritant with Quebec voters.

"The environment was a sensitive spot,'' Dumont said.

"There's no centre-left and centre-right when it comes to the environment.''