Sometimes controversial economist Professor John Quiggin says a number should be put on the value of the internet.

Professor Quiggin made the call at this year's Colin Clark Memorial Lecture in Queensland, saying that a price on the internet is important for ascertaining the value of the National Broadband Network and of digital networks as business infrastructure.

“There's the cable and you pay for that but nobody has ever really measured what you can do with what the cable makes possible,” Quiggin said.

“How can it be measured? We've had a long time to tackle the problem and we haven't really done anything about it.

“With the industrial economy we had a very sharp division between the household sector and the market sector,” he said.

“We still think we can do things the old way, based on an industrial model but, more and more, it's ceasing to have any real meaning.”

The cost-benefit analysis of alternative NBN models would be affected by a figure placed on the less tangible elements of the internet.

Professor Quiggin says in the 21st century digital economy, value is primarily derived from the flow of information rather than physical inputs and outputs. He highlights this as a main reason for economic assessments to be updated.