The Coalition will unveil its plan for a cheaper alternative to Labor's national broadband network on Tuesday, as both sides bicker over election spending costings and budget savings.
Broadband is one of the few major points of difference between the government and opposition, with the coalition warning Labor's $43 billion high-speed fibre network could end up being "a white elephant".
The coalition's plan will offer a mix of fixed line, wireless and satellite access, but at a much cheaper cost for taxpayers and consumers.
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.
Former Liberal frontbencher Nick Minchin, who helped design the coalition version, said the government's plan to roll out fibre cable across the country was "wasteful and expensive".
"It's a huge risk of being a great, big white elephant," he told ABC Radio on Tuesday.
Senator Minchin would not be drawn on the details of the coalition plan or how much it would cost, leaving that to an announcement by Opposition Leader Tony Abbott in Sydney later on Tuesday.
But the announcement could be overshadowed by Labor claims of an $800 million black hole in coalition budget costings.
Coincidentally, it involves planned savings from scrapping the national broadband network.
The coalition says doing that will save $2.44 billion over the next four years by not having to pay interest on the amount the government intends to borrow for the network.
But a Treasury analysis, released to The Sydney Morning Herald, estimates the saving will be $1.6 billion only.
Treasurer Wayne Swan leapt on his department's finding.
"There's certainly an $800 million hole in a budget saving that they are claiming," he told Fairfax Radio.
Opposition treasury spokesman Joe Hockey accused Labor of "playing games".
"This is a secret Treasury document ... that we have not seen," he told ABC Radio.
The coalition has accused Labor of having its own black hole worth $3.4 billion.
Opposition finance spokesman Andrew Robb says Labor promises amount to $5.8 billion, more than the $2.9 billion it claims in policy documents.
Identified savings added up to only $2.4 billion.
The additional spending commitments were being used as part of sand-bagging exercise to bolster Labor's marginal seats, Mr Robb said.
"(Prime Minister) Julia Gillard and Wayne Swan must say where this money is coming from," he said.
