It is a classic case of the Gillard government playing politics over exclusive economic matters, the Coalition said on Thursday, criticising a costing analysis of the opposition tax policies that made its way to media firms.

Shadow treasurer Joe Hockey cried foul although he conceded that his counterpart, Federal Treasurer Wayne Swan, was partly right in arguing that economic policies espoused by the Coalition are of public domain and therefore fair game for scrutiny.

He would not counter that line of argument, Mr Hockey told The Australian Financial Review on Wednesday, but the rub was created when the costing results were made public, which he added was not the practice of previous Liberal governments, as claimed by Mr Swan.

"I spoke with Peter Costello last night and he could not recall a single occasion when he was treasurer when a Treasury minute was deliberately released to the media in order to score political points against the Labor Party," The AFR reported Mr Hockey as saying.

Mr Costello served as treasurer during the John Howard government.

More importantly, the government needlessly chose to politicise the whole process by "asking for a costing of an opposition policy and then leak it to the media," the chief economist for the Coalition stressed.

"It is an unacceptable use of a government department engaged in a political processes," Mr Hockey said, adding that Prime Minister Julia Gillard and Mr Swan crossed the line by the dragging the rather independent Treasury into the messy game called politics.

But the treasurer dismissed the notion that the assessment of Coalition policies, which suggested that tax programs by Opposition leader Tony Abbott would burden Australian business of more than $17 billion in only four years of Liberal-National rule, was wholly motivated by Labor politics.

"Treasury regularly gives us information on policies or particular proposals which may come from a number of groups," Mr Swan told Sky News in an interview Wednesday.

"It's very important to have an informed debate about the cost of various alternatives . . . and the Treasury has always provided those sorts of numbers to governments of both political persuasions," the Treasurer added.

Ms Gillard echoed her treasurer's claim that the policy costing from the Treasury was all routine and did not exceeded its independent function, adding that "Australians are entitled to that information."

"No amount of spin from the Opposition gets away from the simple fact that three of the policies they say they are committed to have been costed, and they will cost businesses more than $4 billion in the first year," the prime minister told ABC.

However, the Coalition costing report leak was far from alarming at the moment, the Australian Chamber of Commerce and Industry (ACCI) said Wednesday, adding that the analysis was far from being broad as it left out assessment for two controversial measures - the carbon and mining taxes.

"We'll be looking at the complete tax policies of both parties and clearly some of the major elements of that including the abolition of the carbon tax and mining tax which we have opposed," ACCI Director Greg Evans told ABC.