The opposition's campaign spokesman Jim Chalmers says shadow treasurer Chris Bowen has been hard at work putting the numbers together, with the pair set to release the figures on Friday.

"So we can take to this election a more responsible set of books than our political opponents and more responsible approach to the economy and the budget," Mr Chalmers told reporters in Canberra on Thursday.

"Budgets are about choices. We choose better hospitals and schools, not more cuts.

"We choose getting wages moving again and dealing with the cost of living and not more tax loopholes for the top end of town."

Mr Chalmers says the party's policies will be partially paid for by making multinationals pay more tax, and he doesn't foresee a Labor budget returning to the red.

Treasurer Josh Frydenberg says Labor has been unable to explain the impact of its superannuation plan, pay top-ups to childcare workers and the impact its negative gearing changes will have on the housing market.

""Right across the board, Labor has many, many questions to answer," he told ABC Radio National.

In his budget reply speech Labor leader Bill Shorten pledged to return the budget to surplus in 2020, in line with the coalition's promise, but deliver bigger surpluses over the next decade.

He also flagged matching the coalition's income tax cuts for those earning under $126,000 a year and extending proposed tax cuts for people earning under $40,000.

There is also expected to be more funding for health, education and infrastructure.

Australian Associated Press