OTTAWA - Leaks from Tuesday's federal budget suggest the governing Conservatives are hoping to hold off a spring election by meeting several of the NDP's spending demands.

A key demand of the NDP -- more support for low-income seniors -- is going to be included in the budget, The Canadian Press has learned.

Government sources say the budget will deliver on two other of the party's demands -- re-introducing the home energy retrofit program at a cost of $400 million a year, and an initiative to attract doctors and nurses to remote and rural areas by forgiving their student loans.

The decision to increase benefits for single, low income seniors was made at a cabinet retreat in January.

The source said the boost would not cost as much as some are estimating, suggesting it will fall short of the NDP's request for $700 million in additional benefits.

Although all three opposition parties have issued demands, the Harper government only needs the support of one of those parties to survive a confidence vote on the budget.

Any respite from defeat might be brief. The Liberals are girding to bring in a non-confidence motion by week's end that would seek to condemn the government for alleged ethical lapses and abuse of power.

If Finance Minister Jim Flaherty decides to spend money to buy NDP support, he has some unreported resources for the job. According to economists who briefed Flaherty on the economy earlier this month, Ottawa likely has about $3 billion in extra revenues this year to pay for additional spending.

Flaherty offered few clues at a made-for-TV fitting of twice-resoled shoes in step with the frugal, stay-the-course messaging of the Conservative government.

The budget will contain some new spending for families and to help create jobs, he said, but the focus remains on eliminating the deficit at the appointed fiscal year 2015-16.

"One of the goals of the budget is to make sure we stay on course, maintain the fiscal track that we set out in the fall update and move back to a balanced budget, and at the same time make some investments to promote economic growth, jobs," he explained.

The list of spending could include:

-- Help for seniors without benefit of a pension, likely through a boost to the guaranteed income supplement.

-- A tax credit for parents who enrol their children in artistic activities.

-- A two-year extension of a program helping firms buy efficiency-enhancing machinery and equipment.

-- Modest measures on pension reform and on financial literacy.

-- The sources said veterans will get help to transition into civilian life through a new apprenticeship program in the construction industry.

-- And at least two research bodies will get money -- $50 million for the Perimeter Institute for Theoretical Physics in Waterloo and $4 million for the Thunder Bay Regional Research Institute.

The remote health care initiative will forgive up to $40,000 in student loans for new doctors, and $20,000 for nurses, who provide health care in sparsely-populated areas of Canada.

But with the opposition parties pounding on election drums, none of the measures may see the light of day or even get to a vote in the House.

Flaherty has passed an extraordinary five budgets in a row as a minority finance minister. He's counting on a sixth.

"I hope we vote on it. I hope it's passed. There are some very good measures in the budget," Flaherty said.

All three of the opposition parties have issued their conditions for support.

The Liberals are unlikely to be swayed unless Flaherty backs away from a plan to keep reducing corporate tax rates, a non-starter for the Harper Conservatives.

The Bloc Quebecois has suggested it would support the budget if it included $2.2 billion for Quebec to harmonize its sales tax.

The Quebec government says it has crafted a draft agreement that is now in Ottawa's court. But in response to a question in the House, Natural Resources Minister Christian Paradis said while negotiations have gone well, there is no deal yet.

Flaherty appears to have room to satisfy at least some of these demands.

Economists who met privately with Flaherty two weeks ago say he has about $3 billion, and possibly more, up his sleeve that wasn't there at the time of the update last fall thanks to faster than expected economic growth.

They told Flaherty the economy will expand by about 5.8 per cent this year in nominal terms -- which includes inflation and is directly tied to tax revenues -- more than one point higher than the previous estimate.

In dollar terms, nominal gross domestic product is running at about $23 billion more than was expected in December, yielding the government an anticipated $3 billion extra in corporate and personal taxes.

Revenues have also been coming in faster this year, which means Flaherty is in position to report that this concluding year the deficit will shrink to under $40 billion, rather than the $45 billion projected in the fall.

"It does seem like they have a little more room to manoeuvre, so I wouldn't be surprised if we see some little wrinkle that might please the electorate," said Douglas Porter, deputy chief economist with the Bank of Montreal.

The more likely option is that Flaherty will hold the line on spending, as he has promised to do all along, however.

TD chief economist Craig Alexander noted that the changing course now would undercut the government's carefully crafted image as responsible managers of the government books.

As well, he said Flaherty's plan for eliminating the budget entails ambitious spending controls few think will possible to maintain for the three or four years required.

"The fact that income in the economy is growing faster than previously anticipated does give them some flexibility, but I think the flexibility is very limited," he said.

"The fact tax revenues are coming in better makes life easier on the government, but make no mistake, the recovery is not going to be adequate to eliminate the deficit on its own."