NBN 'to stay within budget'

NBN Co remains "very comfortable" about staying within its forecast $34.7 billion capital cost for rolling out the National Broadband Network, chief executive officer Mike Quigley says.

Costs of the rollout had fallen significantly since the completion of initial connections, he told the parliamentary joint committee on the NBN in Sydney on Friday.

And NBN Co still had $3.6 billion in contingency funding it had not yet touched, Mr Quigley said.

He said NBN Co was confident it could bring the project in within the timetable and budget.

"I'm happy with the progress NBN Co has made ... it's in my view almost exactly in line financially with what we predicted," Mr Quigley said.

The public hearing heard that more than 68,000 brownfield sites had so far been connected, following the revising down of connection targets earlier this year.

Mr Quigley said take-up by customers was "growing quite rapidly" and some areas, such as Kiama in NSW, had shown a 60 per cent take-up rate, which was "quite astonishing".

"Those are the kind of take-up rates when we talk to operators around the world they really can't believe."