Mr Frydenberg will hand down his first budget on Tuesday, including fresh tax relief and a range of other sweeteners, with a federal election only weeks away.

Economists have forecast the government will have billions of extra dollars to play with than projected in its last budget update in December.

The extra revenue has come through higher commodity prices, which have meant companies paid more tax.

More Australians getting jobs has also helped, raising the amount of tax paid overall by individuals.

But the treasurer says the good news in this year's budget, including a surplus forecast at the end of 2019/20, is "no accident".

"It's the product of responsible decisions - difficult but necessary decisions," he told reporters in Canberra on Tuesday morning.

Labor Leader Bill Shorten said it was the mining industry and Australian workers who have done the hard yards.

"If we have a surplus, I will not thank the government. I will thank the Australian people and thank our export resources industry," he told reporters.

"It is that quantity of coal and iron ore going to North Asia which has done the heavy lifting. But, of course, you have got to be careful of relying on commodities to sustain us."

Extra tax relief is expected to be on its way for low and middle-income workers earning up to $90,000 a year, who will be given an annual boost of about $1000 on top of tax breaks they received last year.

Mr Frydenberg is also expected to announce the government's current net debt of about $370 billion will be wiped out within 10 years, The Australian reports.

It said the budget will feature significantly higher surpluses, while the deficit for this financial year will be lower than the $5.2 billion forecast in the mid-year update, marking a $10 billion turnaround on last year's budget estimates.

Finance Minister Mathias Cormann earlier dismissed the suggestion the government had been handed a lucky windfall by high commodity prices.

Such prices have been lower under the coalition than they were under the previous Labor government, he said.

"I completely reject the proposition of revenue spikes," the minister told reporters in Canberra on Monday.

"This proposition that somehow we've been the beneficiaries of revenue windfalls, when we had to write down $180 billion worth of revenue that Labor had previously assumed out of our budget, is ridiculous."

The budget will be publicly released on Tuesday at 7.30pm, a few hours after the Reserve Bank of Australia's monthly board meeting.

Economists are expecting the board will keep the interest rate on hold at its record low of 1.5 per cent.

Australian Associated Press