OTTAWA (Reuters) - Canada’s minority Conservative government has made a series of last-minute budget concessions in a bid to win enough opposition support to avert an early election, a government source revealed on Monday.

The government will present its budget on Tuesday and needs the backing of one of the three opposition parties to pass the document. If all three vote against, the Conservatives will fall, pushing Canada into its fourth election in seven years.

The source said the government would extend a program to pay people who had made their homes more energy-efficient and would also help doctors and nurses move to rural areas. Both steps touch on demands the left-leaning New Democratic Party has made as a price for supporting the budget.

“We have been clear we do not want an election. We are serious. We are going to put forward a budget that is in the best interests of all Canadians,” the source told Reuters.

“Where the opposition have made reasonable suggestions, we have listened and it is clear that we have acted,” said the source, who asked not to be identified.

The concessions mark a major change in attitude by the government, which as recently as a few days ago had been saying it could not meet many of the New Democrats’ demands.

Polls show the Conservatives, beset by a series of ethical problems, are unlikely to gain a majority in an election now.

“We hope opposition members of parliament will say no to an unnecessary and opportunistic election,” said the source.

Avoiding an election would be a relief for New Democrat leader Jack Layton, who was diagnosed last year with prostate cancer and who had hip surgery this month.

A New Democratic party spokesman reacted cautiously, saying the government showed no signs of boosting Canada’s state pension -- another key demand.

Even if the New Democrats back the budget, the government could face a nonconfidence motion which the main opposition Liberal Party says it might present this Friday.

If the Conservatives survive this week they should be able to stay in power for another year at least. Around half of Canada’s provinces are due to hold elections this fall and a federal campaign then would be unwelcome.

Speaking before news of the concessions, Layton said the ethical issues made it harder and harder for the New Democrats to consider supporting the government.

Last week police were asked to investigate allegations of misconduct by a former top aide to Prime Minister Stephen Harper as well as by a former aide to a cabinet minister. Last month, four Conservative officials were charged with violating financing rules during the 2006 election campaign that brought the party to power.

Earlier on Monday, a special parliamentary committee declared the government to be in contempt for failing to provide enough information on the cost of its crime agenda.

“This is not a good day for Canada or Canadians. This is not done lightly,” said David McGuinty, a Liberal legislator.

A Harris-Decima poll for Canadian Press on Monday put the Conservatives on just 34 percent public support, which means they would lose seats if an election were held now. The party had slipped 2 percentage points in less than three weeks.

The Liberals stayed level at 28 percent while the New Democrats edged up 2 points to 17 percent.

($1=$0.98 Canadian)