Tasmanian NBN 10 percent under budget: Conroy

The Tasmanian leg of the National Broadband Network has commenced rollout at 10 percent under budget, according to Communications Minister Stephen Conroy.

Conroy revealed the figure in a debate with his opposite Tony Smith on ABC Lateline last night in an attempt to stymie an argument over cost blowouts on the project.

"We have delivered the Tasmanian project where we've got live services to people in Tasmania now on time and 10 percent under budget," Conroy told the program.

Conroy said other parts of the network spend were on budget, and the Government stlll expected to spend less than $43 billion courtesy of its agreement with Telstra.

Smith remained unapologetic over the Coalition's own $6.3 billion broadband plan, despite again facing tough questions over its technical feasibility.

He branded "ridiculous" suggestions by Conroy that there wasn't enough wireless spectrum to make good on Coalition plans, saying there was "spectrum today that is suitable for wireless".

"It's in a number of bands and there are existing players using that spectrum," Smith said.

Those with 3G spectrum may also wish to "trade it to another player" who could bid for project work under the Coalition plan, Smith said, or wait for the digital dividend - spectrum vacated by analogue TV that could be used for next-generation mobile services.

Smith also faced questions over whether the number of people accessing the Coalition's wireless services would mean slower speeds for users.

"Well, wireless is contended, but the speeds and the technology is getting better all the time," Smith said.

"And we are not only promising wireless."