The company rolling out Malcolm Turnbull’s model of broadband insists it is not replacing the legacy Telstra copper with brand-new copper lines, but it is still buying up approximately 1800 kilometres of copper just to last the next six months.

As part of the shift away from Labor’s fibre-to-the-premises model of the NBN, the company will be using existing Telstra copper lines that go from the street to each premises, and will only upgrade the copper to fibre up to a box, or node, on the street outside the premises.

Last week, Labor opposition communications spokesman Jason Clare accused the  NBN company of rolling out new copper lines to replace the worse-for-wear copper the company had discovered once it began building Turnbull’s version of the project:

“In some places the copper is so bad it has to be replaced. Replacing old copper … with new copper. One contractor told me in Newcastle and the Central Coast 10 to 15% of the copper lines are having lengths replaced. And this is not just happening in Newcastle or the Central Coast.”

NBN denied this in a blog post and again in estimates hearings on Tuesday. In what was often a tense hearing, up against NBN architect and former communications minister Senator Stephen Conroy, NBN boss Bill Morrow said he had been told so far that the copper was “in fine condition”, but admitted the company was negotiating supply of new copper for the network, something that was difficult because copper lines are a scarce resource as networks are increasingly using fibre over copper.

Sydney-based company Prysmian is the current supplier of copper to NBN.

NBN chief financial officer Stephen Rue confirmed in the hearing that NBN had bought 1.8 million metres, or 1800 kilometres of copper worth $14 million, just to see it through the first six months of the fibre-to-the-node rollout.

Morrow said that two different types of copper lines were required, depending on the node NBN uses. “It’s 100 pair and 200 pair type cables depending on the type of the node. To put this in perspective … it’s on average 350 metres [of copper] per node in the [fibre to the node] environment.”

As is often a hallmark of NBN committee hearings in the current Parliament, the mood was often tense, as the former communications minister clashed with NBN executives and government senators, leading to several breaks in the hearings while Conroy pushed for more time for questioning, and fought with Morrow on his work history.