The national broadband network has been a massive boon for the consultant industry with NBN Co paying out over $50 million for external reviews in financial year 2014 alone.

NBN Co told a Senate Select Committee on the NBN that it had spent $50.5 million on fees and travel expenses for consultant groups in the 12 months ending June 30, 2014.

NBN Co spent $73.05 million in "external service costs" during financial year 2013, up from $67.8 million from the previous year. Credit:Rob Homer

"Working with the executive committee, we have decided to drop down into a number of detailed reviews," NBN Co chief executive Bill Morrow told the Committee earlier this year. "We have been doing operational reviews around our IT structure, systems and architechture."

Boston Consulting Group (BCG) was the biggest winner, having received $13.49 million to help run a review of its rollout options, the fixed wireless and satellite service rollout and a range of other services.