Demand modelling specialists were instructed not to conduct a detailed revenue calculation from potential NBN business customers while preparing a key input to the project's cost-benefit analysis.

The analysis prepared by the an expert panel led by former Victorian Treasury head Michael Vertigan was intended as a comprehensive comparison of the costs and potential revenue of the current and former governments' respective NBN models. It was delivered in August.

NBN review panel chair Dr Michael Vertigan. Credit:Nic Walker

Central to determining the viability of the different technologies in the broadband infrastructure project - essentially whether fibre to the node or fibre to the premises was more likely to succeed - was the estimation of how much consumers and businesses were prepared to pay for faster broadband.

Business revenues account for about half of Australia's $40 billion-plus telecommunications market, but companies' willingness to pay for a better service were not fully investigated, according to John Rose, director of the University of South Australia-affiliated Institute for Choice (I4C).