Opposition leader Peter Dutton says the federal government cannot "credibly take credit" for what could be the largest budget surplus ever delivered.
The opposition leader says the Albanese government was on track to deliver a one-year surplus but then fall back into the red.
"They achieve a surplus in this year because that's what they've been bequeathed from a coalition government of nine years," he told Sky News on Sunday.
"And then when they're on their own over the next five, six, seven years, all projected to be deficits."
Mr Dutton also said higher royalties and company tax receipts from the resources sector had made a "very significant" contribution to the improved bottom line.
"I just don't think (Prime Minister) Anthony Albanese could credibly take credit for all of that," he said.
Treasurer Jim Chalmers flagged the possibility of a 2022/23 budget surplus "substantially" bigger than the minor $4.2 billion forecast in the May budget nearly two months ago.
Federal budget data through to the month of May suggests this surplus could be among the largest on record, with the underlying cash balance for the 12 months to May coming in at $19 billion.
The largest-ever surplus was in 2007/08, at $19.8 billion.
Higher revenues from taxes, as well as less spending, contributed to the healthier-than-expected result for May.
On Saturday, Prime Minister Anthony Albanese said the government had managed to turn a $78 billion deficit forecast under the former coalition government a year ago into a surplus in excess of $4 billion.
He also said it pointed to the government's sound budget management that would put downward pressure on inflation.
"(Australian families) know that responsible economic policy from the federal government is important and has a flow-on impact that is positive for families."
Australian Associated Press