SHADOW Treasurer Joe Hockey attacked "rubbery" government figures as a key part of his budget reply speech in Canberra on Wednesday.
He said the government abandoned historic data when increasing costs in the budget and then used it when it decreased costs.
"They have junked a long term average for education only to use a long term average for boat arrivals," he said.
"These are some of the tricks that undermine the budget and reflect poorly on this government."
Mr Hockey also attempted to bolster the Coalition's small business credentials in the lead-up to the September election.
He said stability for the sector did not come from "a Labor Government that has had five small business ministers in 15 months".
Mr Hockey also took a stab at the tax office, repeating his "deep reservations" about the bureaucracy's ability to administer tax arrangements.
To that end, he committed the Coalition to creating a standing committee for oversight of tax administration.
"So our timeframe should allow a proper evaluation of the ATO's new approach to independent review of disputes," he said.
"However, if the oversight committee believes it's necessary, then the Coalition stands ready to break up the tax office, so that its policeman functions are separate to its responsibility for administering the tax system."
While light on policy detail, Mr Hockey said the Coalition would push to create a sustainable budget, with any new policies balanced against savings.
But he would not release any specific costings of the Coalition's current policies, delaying details until the election campaign proper.
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