The Coalition has attacked the NBN Co Corporate Plan, calling the additional $2 billion cost to the taxpayer a "blow out".
Opposition communications spokesman Malcolm Turnbull said the $27.5 billion the Federal Government announced it would contribute in taxpayer funding to the NBN was already more than it estimated just six months ago.
In May 2010, the NBN Implementation Study estimated taxpayer inputs of $26 billion.
"This is already blowing out," Turnbull said.
Turnbull and Opposition leader Tony Abbott also criticised the NBN Co wholesale prices revealed in the business plan, saying it would only lead to retail prices that were "comparable" to those available for ADSL services today.
Turnbull said the NBN originally promised to deliver "universal and affordable broadband."
The prices in the Corporate Plan were "comparable – it's certainly no cheaper – for ADSL services at 12 Mbps-plus," Turnbull said.
"This is not the nirvana of cheaper broadband to Australians."
Turnbull also criticised the length of the NBN business plan released today. Initially said to be over 400 pages, the version made public was only 160 pages, leading to concerns that much of the detail had been redacted.
"This is not a business plan [that's been released]," Turnbull said. "It's only got summary financials".
Turnbull claimed the plan showed "no evidence" of a requirement for 100 Mbps internet speeds in the household sector and that those who had inadequate broadband speeds now would have to wait "over a decade" to get better services.
Opposition leader Tony Abbott used a press conference to renew calls for a cost benefit analysis for the NBN.
"The government still does not trust its case for this kind of scrutiny," Abbott said.