In the letter the AAB, which includes telcos Vocus Communications, EFTel, AAPT, BigAir and Pipe Networks founder, Bevan Slattery, urged the Senators to heed its call, stating that each of its members had different things to gain and lose under an NBN.

"Some have dismissed our views lightly as being self-interested, even though credible national and international voices have recently expressed their own doubts or criticisms of the NBN proposal," the letter reads.

"We welcome this debate and are excited to have helped to generate it. We now believe it is time to have a credible, independent, dispassionate and rigorous analysis done of the NBN proposal."

While supportive of the need for a national broadband capability, the AAB stressed the Senators' need to ensure the Government's policy was sound and that taxpayers' money was spent well and wisely.

"...Policy of this magnitude which carries with it fundamental changes to the entire fabric of the national telecommunications landscape and re-creates a new government-owned monopoly requires Members of Parliament to ensure such a policy is the best policy for the future development of the country, and in particular the delivery of the most efficient investment by the Australian taxpayer," the letter reads.