No 'blank cheque' for NBN, Turnbull tells Lateline

Even if a cost-benefit analysis supports a fibre-to-the-home network.

Opposition communications spokesman Malcolm Turnbull refused to be drawn on whether he would support the National Broadband Network if a cost-benefit analysis concluded it should proceed during a televised debate on the ABC last night.

"Malcolm was asked two days ago in a trade publication if a cost-benefit analysis came back unambiguously yes, it was positive, would you still back it, and Malcolm wouldn't," Communications Minister Stephen Conroy told Lateline host Tony Jones.

"This is just opposition for opposition's sake."

Senator Conroy was following Monday's CRN video interview with Turnbull in which the Opposition spokesman was asked how a cost-benefit analysis should proceed and whether he would support its conclusions even if they were counter to Coalition policy, which was not to build the NBN.

Jones asked: "Malcolm Turnbull, if they did a cost-benefit analysis and it said pretty much what the McKinsey report says, would you then agree that it's a good idea?"

Turnbull replied that the $25 million McKinsey study earlier this year was not a cost-benefit analysis.

"A cost-benefit analysis that posed the problem, the digital divide, as Stephen's [Conroy] defined it, and then looked at different ways of addressing it, with different technologies, if that came back, I would read that very, very carefully," Turnbull said.

But when pressed by Conroy ("you won't even commit if it says yes") Turnbull said "hundreds of billions of dollars  have been wasted" in the hopes of "build it and they will come".

Earlier this week, Turnbull told CRN that "no one in their right mind would ever give a blank cheque to an analysis that hasn't been done".

"But a good cost-benefit analysis will be very transparent, set out all its assumptions, will enable people to play with those assumptions, to change them and form their own view about them and it will inform the debate so it could be very influential, absolutely, but no one's going to give it a tick in advance."