The federal treasurer has downplayed the bungling of JobKeeper figures, saying the massive $60 billion cost downgrade is not an excuse to spend more money.
Treasury released new data on Friday showing the JobKeeper wage subsidy program is now expected to cost $70 billion instead of $130 billion.
In a joint statement with the tax office, it revised its figures for the program, with the number of employees forecast to be assisted being 3.5 million instead of 6.5 million.
Treasurer Josh Frydenberg said this was good news for the taxpayer.
"This is all borrowed money," he told ABC on Friday.
But he said the government wouldn't be expanding the program to casuals and the arts sector.
"This is not an invitation to spend more money," Mr Frydenberg said.
Labor leader Anthony Albanese said the mistake was an embarrassment for the coalition and it should now expand the JobKeeper program.
"This is a government that couldn't run a bath let alone be good economic managers," he told reporters in Sydney.
Mr Albanese said by excluding casuals and other ineligible workers from the payment, the government would prolong Australia's economic recovery.
About 1000 businesses made "significant errors" when reporting the number of employees estimated to receive help.
The most common error was reporting the amount of assistance they expected to receive rather than the number of employees expected to be eligible.
For example, instead of writing one eligible employee businesses wrote 1500 - the amount of dollars received each fortnight through the program.
ATO second commissioner Jeremy Hirschhorn said the incorrect numbers were only used for early estimates by businesses and not the final payouts.
Employers were then contacted by the tax office to provide names and other details for each employee they wanted to receive JobKeeper.
Mr Hirschhorn said it was an unfortunate misunderstanding.
"This number had nothing to do with the amount they were ultimately paid," he told reporters in Sydney.
"There have been no underpayments or overpayments."
The $1500 fortnightly payments began flowing to employers earlier this month and are legislated until the end of September.
The program is up for review in June.
The Morrison government has ruled out further extending the program to include casuals and migrant workers.
Treasury says its overall view of the labour market is unaffected by the reporting error, with expectations unemployment will rise to 10 per cent.