"We're not giving up on fibre-to-the-premisess and if it ends up being cheaper than fibre-to-the-node, we'll do it," Mr Morrow said. "One of the manufacturers recently took us through an innovative way to reduce cost to get fibre to the home. We were thrilled to hear this."

Mr Morrow did not refute repeated suggestions from Greens senator Scott Ludlam that, based on NBN Co's flexible approach, it was possible that fibre to the premises could constitute between 80 and 90 per cent of the network.

The NBN Co chief said that in order to provide a minimum standard of service, it could use FTTP technology in cases where Telstra's copper assets have leaked or eroded, or have not been renewed, refreshed, replaced in an appropriate timeframe.

"If we find copper inadequate for us to serve fibre to the node, either to produce the speeds available or if the maintenance side is just too far gone ... even though we're committed to doing FTTN, will just take FTTP or an alternative tech."

However, he did not go into details over how this decision may affect the re-negotiations for Telstra's copper network. He declined to set a deadline for resolution. In February Mr Turnbull said the $11 billion dollar replacement deal would be completed by mid year.