RIVIERE-DU-LOUP, Que. — A day after Michael Ignatieff declared himself willing to try to form a government even if his Liberals finish second in next month's federal election, Stephen Harper rejected the idea a Conservative minority would partner with other parties to shore up a government.

"I don't accept the question," Harper said bluntly, when asked on Wednesday if he'd be willing to work with other parties in a minority setting.

The two leaders' public statements this week on the possible architecture of the government after May 2 have reopened talk of coalitions, co-operative agreements and other possible outcomes if no party wins an outright majority.

Saskatchewan Conservative Premier Brad Wall called Ignatieff's approach "offensive" and said he was "deeply troubled" by it.

"While I understand that the scenario spelled out by Mr. Ignatieff is within the conventions of our parliamentary tradition, the last thing our country and our still fragile economic recovery need right now is a period of instability caused by a constitutional dispute over who should be the government," Wall said.

Earlier this week, Ignatieff said in a CBC interview that he'd be willing to work with leaders of the other parties — "even Mr. Harper" — if Canada, once again, finds itself with a minority Parliament.

But Harper said he believes the Liberals, NDP and Bloc Quebecois have already decided to defeat the Conservatives soon after the election in order to form a coalition government.

"If you look at what they're saying in this campaign, it is very clear. They're saying that even if we receive a mandate from the people, they will defeat us on our budget if they can. They will get together and form another alternative of some other kind of government."

In fact, Ignatieff left the door open Wednesday to compromising on a future budget if introduced by a Tory government and blasted Harper for not compromising when he introduced a budget in March, before the election.

Harper has explicitly asked voters for the first time to give his party a majority, which will require the Conservatives to add at least 12 seats to the 143 the party held at dissolution.

Ignatieff's efforts to close the gap between Liberals and Conservatives have not borne much fruit. Even his most recent tactic — selling the Liberals as the party most able to protect Canada's flagging health-care system — appeared to be flatlining.

According to results of an Ipsos Reid poll released Wednesday to Postmedia News and Global National, Canadians trust the NDP most when it comes to health. Forty-six per cent of likely voters favoured Jack Layton and his party to manage the file. Thirty per cent of respondents trusted the Conservative party most on health care and 20 per cent reported trusting Ignatieff and the Liberal party the most.

Harper said Wednesday he would be "honoured with any mandate" his party receives from voters on May 2. But he refused to discuss what changes to the party's platform he would be willing to accept to keep the Conservatives in power if they win another minority.