The minister in charge of Australia's broadcasting standards has dropped the F-word live on national television during children's viewing hours.

Communications Minister Stephen Conroy was answering an AAP question at the National Press Club in Canberra about the risk for investment in Australia when he used the word.

"In terms of sovereign risk, I love the debate about sovereign risk," he said.

"I have seen a new definition of sovereign risk; it is asymmetrical.

"If a tax goes up, God, that is sovereign risk. But if a tax goes down, f***ing fantastic."

He quickly added: "Excuse me."

The next program on the ABC's schedule was the G-rated Meerkat Manor, an animal show popular with young children.

Senator Conroy, who kept his job in yesterday's cabinet reshuffle, is the minister overseeing broadcasting standards.

He used his speech at the Press Club to to discredit the Coalition's broadband policy.

Opposition communications spokesman Malcolm Turnbull has proposed a mix of optical fibre, wireless, DSL and satellite technologies.

He has consistently labelled the Government's National Broadband Network as an expensive white elephant.

But Senator Conroy rejects that and says Mr Turnbull's plan is severely limited.

"Building FTTN (fibre to the node) which delivers such low upload speeds would be like building the Sydney Harbour Bridge with only one lane in only one direction and then making people row a boat back across the harbour," he said.

Sloppy and vulgar

Mr Turnbull later attacked Senator Conroy for making a "sloppy and vulgar" speech.

"It may have been the first time a communications minister has used such crude language on television during children's viewing hours," Mr Turnbull said in a statement.

"But it is not the first time this minister has delivered unsourced and unjustified assertions about technology."

Mr Turnbull said Senator Conroy dismissed any alternative to his preferred fibre-to-the-home network as being utterly inadequate even though other technologies were being used to deliver next-generation broadband "in every other major economy in the world".

Taking aim

Senator Conroy took aim at the Productivity Commission after it last week released a report saying the commercial rate of return of 7 per cent for the NBN is too low.

He says the Commission does not understand broadband policy and that it should understand that perfect competition in the sector has not worked and he jokingly took a swipe at the Commission's way of thinking.

"Three people on a desert island - a physicist, engineer and an economist - and they've got a can of beans. How are they going to open a can of beans to eat before they starve?" he said.

"The physicist suggests we build a fire, eventually it'll burst open. The engineer devises a way to cut it open. The economist starts off by going, 'let's assume we've got a can opener'.

"Welcome to dealing with the Productivity Commission."

ABC/AAP