Kevin Rudd and Tony Abbott face the same rocky economic road, but are driving very different political cars.

The prime minister's focusing on supporting "jobs and growth", by allowing larger budget deficits before returning to surplus in four years.

The opposition leader's targeting government waste, spending and debt, as well as tax cuts to build a "strong and prosperous" economy.

These are the key messages each will take to a likely September 7 federal election, which could be called as early as Sunday.

But the factor looming over both models is the outlook for the global economy.

Labor believes it's done the best it can to head off the negative headwinds coming from abroad, while making $17 billion in savings and giving the economy the room to move.

It argues the coalition, if it wins government, faces the same conditions - so what will it do to protect jobs?

"We are calling it as we see it," Treasurer Chris Bowen says.

"There are challenges in this environment ... that require careful management."

The careful management means taking the budget further into deficit over the next two years.

The upside for Labor is that it will have budget room to make spending promises during an election campaign focused on jobs, education, industry, skills and infrastructure.

Labor can also boast no cuts to services, family payments or pensions and the retention of the cash payment school kids bonus, which the coalition will abolish.

The downside for Labor is the deficits are large and gross national debt is heading towards $400 billion. The opposition will want to know how it's going to pay that down.

Abbott says the government has lost fiscal control.

"What you get from Labor is more spending, more deficits and more boats," he adds.

Labor argues cutting government spending now would be irresponsible, especially for business and industry, and wants to know what Abbott proposes to do.

For voters, the main question is which side will be the better economic manager, given the circumstances.

One thing's for sure, Australia could be in for a rough ride.