The National Broadband Network has been met with a clamor for transparency over its budget as stage one of the rollout for the project saw 90 percent of funds being used to connect just half of the houses in the covered areas.

Communications Minister Senator Stephen Conroy says that the national rollout's first stage in Tasmania has gone according to plan.

"We came in on budget, in fact, 10 per cent under budget and on time," he said.

Conroy's statement means that nearly all the project's budget was used to connect only half of the homes that opted for the installation of a broadband fibre optic cable connection.

The Government's earlier announced that its target is 80 percent.

"We hope that coming in under budget that they have still accounted for connecting the remainder of the homes that haven't already been connected so far," said Andrew Connor from the consumer group Digital Tasmania.

"It's certainly very hard to determine if they're on budget or under budget at the moment because no figures have been released up until this point in time."

"What we need to see is a bit more oversight of the whole NBN project, to publicly admit how much has been budgeted and how much has been spent so far, and what the plan is for the future."

NBN Co says that users who opted not to get the connection will be charged a fee to be connected in the future. Stage one of the project's rollout covered areas in the Tasmanian towns of Midway Point, Smithton and Scottsdale.