Quebec Premier Jean Charest is taking issue with a campaign promise made by Stephen Harper to finance a hydro mega project in Labrador, saying the federal backing would be the equivalent of offering an unfair subsidy.

Harper has promised financial support for Labrador's Lower Churchill hydro project to build power lines from Labrador through Nova Scotia and potentially into the United States, building it into a competitor for Hydro-Quebec.

Charest told a crowd in Quebec City on Friday that Hydro-Quebec had built its system without federal support and that using federal money to create competition was unfair.

"What's never happened in the past is that the federal government intervenes in a market that works well and comes in to change the rules of the market," Charest said in Quebec City. "Quebec developed its network by itself. Hydro-Quebec financed its operations by itself, including the interconnections with our neighbours."

Charest said he was surprised by Harper's sudden promise and suggested it was made to win votes in Atlantic Canada. "It's a political commitment done during a political campaign; we'll see where it leads," he said.

The Conservative Party is walking a fine line in Quebec and Atlantic Canada. It desperately wants to improve on the 11 seats it currently holds in Quebec, but was also shut out of Newfoundland and Labrador in the 2008 election.

Harper's promise comes about a week after the federal government agreed to give Quebec 100 per cent of the royalties from natural-gas deposits in the Gulf of St. Lawrence.

Nova Scotia Premier Darrell Dexter, whose province is a joint partner in the Lower Churchill hydro project, said Quebec has received lots of federal support in the past. He said Charest's intervention could cause "financial injury to the citizens of Atlantic Canada."

Charest's opposition to the Lower Churchill promise came as the premier waded into the federal election campaign on Friday, seeking promises from party leaders.

Charest said he wanted a commitment to replace the Champlain Bridge in Montreal. He added the Davie shipyards in Levis, Que, need to benefit from $35 billion in upcoming military construction contracts and that the province needed clear estimates on how much it would benefit from F-35 or any other fighter jet contracts.

Charest also expressed his enthusiasm for plans to build a high-speed rail line from Montreal to Windsor, Ont.

So far, the only party that has taken a stand similar to what Charest has outlined is the Bloc Quebecois.

"That does not mean the Bloc is an option," said Charest. "I don't personally believe that supporting a separatist party is an option. I believe in Canada, as being in the interest of Quebec. I am going to speak to those issues and the broader issues of all Quebeckers."

With files from The Canadian Press