Opposition spokesman on communications, Malcolm Turnbull, has once again attacked the National Broadband Network (NBN) claiming it will cost more than what most Australians are willing to pay for internet access.

NBN Co is likely to charge retailers such as iiNet or iPrimus $35 per month to sell plans via the fibre optic network. Based on this figure, Turnbull has estimated that retailers will charge their customers approximately $65-$70 per month. He says this figure is more than what most people are currently paying for broadband access, and the "extraordinary" figure will limit the number of people who are willing to sign up for fibre access.

"That is higher than most people are paying now. So there is no reason to believe that the NBN will deliver cheaper broadband. It certainly will deliver faster broadband than many people are getting at the moment, but at an extraordinary cost," he said.

Entry level plans at test sites in Tasmania start at $30 per month, and go up to as much as $160 per month for plans with a larger download quota and faster internet speed.

A spokeswoman for the Minister for Broadband, Stephen Conroy, has argued that competition in Tasmania is already increasing, which will in eventually drive prices down for customers.

"As experience in other markets has shown, the introduction of genuine competition will lead to more choice, more affordable prices and higher quality services," she said.

While the opposition’s policy on broadband is yet to be finalised, Mr Turnbull has indicated that the Coalition will not shift away from their support for a government subsidy in regional areas for wireless and satellite internet access.  Mr Conroy has argued that this will prohibit rural and some outer suburbs from gaining high-speed broadband access.

"We're talking about … Hobart, Launceston, Darwin, Canberra, that wouldn't be [connected] under these sorts of … Turnbull proposals that Barnaby Joyce and Warren Truss signed up to," he said.