A slowing economy, global trade wars and the drought are reasons for higher surpluses, says shadow treasurer Chris Bowen.
Some economists believe the Reserve Bank will cut the cash rate on Tuesday to stimulate the economy.
However, Mr Bowen said the economic situation made it all the more important to balance the books.
"It is a time for bigger buffers, for the government to have more levers at its disposal," Mr Bowen told the National Press Club on Monday.
"I accept that is unusual historically, but we do so deliberately because we think that with interest rates lower and wages growth anaemic and household debt at international record levels, we need bigger buffers - a bigger insurance policy against uncertain international economic times."
Treasurer Josh Frydenberg and opposition treasurer Chris Bowen in the debate at the National Press Club in Canberra.. Source: AAP
Mr Bowen said the fact that the RBA was even contemplating interest rate cuts showed the "real concern about the economy under this government's watch".
Treasurer Josh Frydenberg said Labor's talk was cheap as the party had not delivered a budget surplus since 1989.
He said the decision on rates was one for the independent RBA.
"We know the cash rate has stayed where it has been since mid-2016, so it has been there for some time," Mr Frydenberg said.
"I wouldn't seek to pre-empt those decisions that may or may not be taken, other than to say the fundamentals of the Australian economy are sound."
Meanwhile, Mr Frydenberg says the government won't be revisiting corporate tax cuts for Australia's largest businesses over the next decade.
Senate opposition to tax cuts for the biggest firms forced the government to cut back on its ambitions and deliver them only for small and medium-sized businesses.
Asked what were the government's intentions over the next decade, Mr Frydenberg said: "We're not planning changes on the large companies."
Responding to a follow-up question, he said: "We have no plans to change the company tax rates. We tried that and you know what the story is."
Mr Bowen said the only reason why the tax cuts did not become the law of the land is because of Labor's opposition.
"If the Liberal Party is re-elected and they have a majority through a coalition of chaos with Clive Palmer and Pauline Hanson in the Senate, they will be back there," Mr Bowen said.
"'No plans' is a pretty weak defence for the Treasurer to make."
Asked a third time, Mr Frydenberg said: "I can confirm we are not coming back to the company tax cuts. There you go."
