Shadow treasurer Joe Hockey will use next week's debate with Treasurer Chris Bowen to talk about the coalition's "interim costings".
Opposition Leader Tony Abbott was again challenged by Labor on Friday to reveal the costings of his election promises after an independent analysis suggested he was $30 billion short of producing a better budget bottom line than the government.
Mr Abbott reiterated that all of the coalition's costings and funding measures would be released in the final week of the campaign and in "good time" before the election.
"All of the time we are releasing interim costings and Joe Hockey will have a fair bit more to say about costings at the National Press Club," in Canberra on Wednesday, he told reporters in Darwin.
The analysis by respected economist Saul Eslake showed the opposition had made savings of $13.5 billion rather than the $17 billion it has boasted of.
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
The Bank of America Merrill Lynch economist also said the coalition would needed to make an additional $30 billion of savings.
While this falls considerably short of the $70 billion "black hole" suggested by Labor, it's still a large amount.
Mr Abbott said the analysis contained errors.
"I have a fair bit of time for Saul Eslake, he's a very credible economist, but he's not infallible," he said.
Treasurer Bowen said if the coalition believed Mr Eslake was incorrect they should show their figures to the Australian people immediately.
"It is not simply good enough for them to shrug their shoulders and say it's wrong," Mr Bowen told reporters in Sydney.
"Even it is $30 billion, that is a very substantial black hole for them to fill."
Shadow treasurer Joe Hockey said he wasn't going to cop a lecture from Labor.
"Our numbers will be, and are, more robust than anything that Labor has presented for six years," he told Sky News.
"They are desperate and hysterical."
He also said Mr Eslake got his figuring wrong.
Shadow assistant treasurer Mathias Cormann said the coalition was "absolutely" standing by its statement it had $17 billion in savings - rather than the lower figure of $13.5 billion.
The analysis may have come to that conclusion because Mr Eslake wasn't "fully acquainted with all the policy detail," the senator said.
