Prime Minister Malcolm Turnbull refuses to be lectured on debt by Labor, saying the opposition went to the 2016 election promising even more debt.
Labor has taken aim at the coalition for allowing government debt to balloon to half a trillion dollars, having come to power in 2013 complaining about a debt and deficit disaster.
Back then debt was heading to $300 billion.
According to the Australian Office of Financial Management, government debt on issue stands at just under $500 billion but will breach that level on Friday when an $800 million bond tender is held.
"We do have a debt problem in this country," opposition finance spokesman Jim Chalmers told reporters in Canberra on Thursday.
Opposition Leader Bill Shorten took up the argument in parliamentary question time, asking the prime minister how the government could afford a tax cut for millionaires.
"Few people are less qualified to give lectures on debt than the leader of the opposition," Mr Turnbull replied.
"He went to an election and he promised more debt. More debt, $16.5 billion of more debt."
Treasurer Scott Morrison said his Labor counterpart Chris Bowen should be apologising to the Australian people.
"He should apologise with all of the spivs on that side of the chamber who, over so many years, racked up the debt in this country and set fire to the nation's finances," he told parliament.
Mr Morrison said from 2018/19 new commonwealth government securities will not pay for everyday expenses, but instead be used to invest in infrastructure.
Mr Bowen described that as one of the "greatest somersaults with pike" in Australian history
"What Scott Morrison is doing is setting up an excuse and an alibi for his failure when it comes to debt," he told reporters.
The budget papers show debt will rise to $606 billion within four years and $725 billion in a decade.
When gross debt was projected to be $300 billion under Labor, Prime Minister Malcolm Turnbull - then in opposition - described it as "frightening" and '"almost inconceivable".
"After four years of (Tony) Abbott and Turnbull, it is long past time for them to accept responsibility for skyrocketing debt and admit they are part of the problem, not part of the solution," Dr Chalmers said.
