Prime Minister Julia Gillard will be in Perth on Friday for the first time in the campaign for the federal election, and will declare that the coverage of the national broadband network will expand from 90 to 93 per cent of the country.

Communications minister Stephen Conroy said half of all eligible Tasmanians have already signed on to the NBN, with Scottsdale, Smithton and Midway Point among the first towns to go online earlier this month.

Senator Conroy said there has been a pleasing level of interest in these communities.

"The cynics, the doomsayers claimed we were only going to get 10 per cent or 15 per cent (on the network)," he told ABC Radio on Friday.

"We've already got 50 per cent signed up."

To increase take-up rates even further, Senator Conroy said he would back a rollout where people were automatically connected to the network unless they decide to opt out of it.

"We believe that the most efficient way to deliver that service is to have that process," he said.

About 90 per cent of Australian homes will now be linked to the network through fibre optics, or an additional 300,000 premises, according to Senator Conroy.

The rest of the country, including some regional and suburban territories, will depend on a wireless system or satellites.

The Coalition pledged to axe the NBN if elected.