Communications spokesman Scott Ludlam now says their support for the $43 billion network is contingent on the Government releasing a $25 million study into the network conducted by McKinsey and KPMG.

Communications Minister Stephen Conroy failed to comply with a Senate order to table the report by 10am today.

On Tuesday, the Australian Financial Review revealed that an earlier network study, obtained under Freedom of Information laws, had relied on Wikipedia to support the case for the national network.

Senator Ludlam said the Government could no longer take Greens support for the bill for granted.

“This is an offensive snub not just to the Senate's accountability role, but to anyone with an interest in whether the NBN can deliver education, health and communications services for all Australians, and the business case behind this massive infrastructure project," he said.

"With the numbers in the Senate so finely balanced and a hostile opposition, the Minister seems determined to burn what little goodwill remains on the crossbenches. The support of the Australian Greens is essential for the Government’s telecommunications agenda to progress. That support can no longer be taken for granted.''