Labor says the coalition is failing its own test when it comes to reducing government debt.
In late 2013, the then treasurer Joe Hockey reached a deal with the Greens to get rid of the $300 billion debt ceiling.
But Mr Hockey soon after issued a direction to Treasury, without having to go through parliament, to ensure the total face value of stock and securities that may be on issue was limited to $500 billion.
Shadow treasurer Chris Bowen said Scott Morrison was about to fail Mr Hockey's debt test and be compelled to issue a new direction this year.
"Joe Hockey set a $500 billion direction on government borrowing and Scott Morrison's own figures show that being met and exceeded by the middle of 2017," Mr Bowen told AAP on Tuesday.
"No wonder Australia's AAA credit rating is currently at risk."
The forecasts in MYEFO show that by June 30 the projected value of Australian bonds on issue will be $496 billion, or 28.3 per cent of gross domestic product.
It's expected to rise in 2017/18 to $539 billion and reach $601 billion in 2019/20.
As of January 13, securities on issue came to just over $466 billion.
Mr Bowen says under Mr Morrison's watch in 2016 the economy lost 50,000 full-time jobs, saw record under-employment and low wages growth and a negative quarter of growth.
Mr Morrison, who is on leave, argues Labor is blocking budget savings, which would speed up the government's ability to pay down debt, and opposing the government's business tax cuts which would drive investment.
The treasurer is due to return from leave later this week, when he will head to Germany for a G20-related meeting.
"The biggest danger to Australia's AAA credit rating is Labor and their blocking of sensible measures in the Senate, as well as their continuing trajectory of reckless spending," acting treasurer Kelly O'Dwyer told AAP on Tuesday.