The federal government has been caught out making false claims about the union connections of Labor frontbenchers.
Federal Treasurer Peter Costello was forced to admit that "a couple of" Labor MPs featured in a coalition campaign were not union officials.
The advertisement shows pictures of the 30 potential members of a Labor government ministry, with 23 coloured red and labelled "unionist".
Labor's treasury spokesman Wayne Swan and small business spokesman Craig Emerson are both cited as among the "anti-business union officials".
But both said they had never worked for unions.
Labor is calling for the ads to be taken off air.
"They never let the facts get in the way of a scare campaign," Mr Swan told the Nine Network.
"I've never been a union official ... I have a broad and varied experience and I'm most certainly not anti-business."
Mr Swan said he had been a union member since university.
But his background was as a lecturer at Queensland Institute of Technology for 12 years and a party official before being elected to parliament in 1993.
Dr Emerson said he had held many jobs, including economist at the United Nations, adviser to Bob Hawke, small business owner and director general of the Queensland Environment Department, but not union official.
"Stop making false claims and get these wrong and desperate ads off the air," he said.
The treasurer was caught out in an "embarrassing gaffe" on ABC television's Insiders program, Dr Emerson said, when he could not name the two frontbenchers' union connections.
In an exchange with host Barry Cassidy, Mr Costello conceded only Mr Swan had been a union member.
"Well, he was an AWU member, a member, wasn't he?" Mr Costello said.
"Correct," Mr Cassidy replied.
"Craig Emerson? I don't know about Craig," Mr Costello said. "He was a union official, wasn't he? You sure he wasn't a branch official?" Mr Costello continued.
"No," Mr Cassidy said.
"Ok," the treasurer replied.
The coalition campaign headquarters later released a list of the union connections of Labor's frontbenchers, showing 21 - not 23 as claimed in the ad - were ex-union officials.
But the list backs up the advertisement's claim that 70 per cent were former union officials.
"Are there not enough (union officials)? A couple of them are not out of, what, 30?" Mr Costello told ABC TV.
"We can rest assured because a couple of Rudd's front bench are not former union officials. I'll sleep easy tonight."
Deputy Labor leader Julia Gillard used former prime minister Bob Hawke to illustrate her claims a Labor government would not be run by the unions, irrespective of their connections.
Ms Gillard, herself a former president of the group now known as the National Union of Students, said Mr Hawke was a "quintessential union boss" under the Liberal Party's definition.
"Now is anybody suggesting that Bob Hawke's government was told what to do by the unions?" Ms Gillard told Network Ten.
"Well of course you couldn't suggest that, because Bob modernised this economy in the teeth of union opposition.
"So this analysis that because someone may for part of their working life have worked for a trade union means somehow that they will be directed forever by the trade union is really just laughable."
Ms Gillard said Labor would be making decisions in the national interest.