NBN Co’s chief operating officer, Greg Adcock, said fibre-to-the-node trials were ‘‘under discussion’’, but had not started. The trials would look at how much of Telstra’s copper would need to be remediated and how a rollout would occur.

‘‘The trial is going to have a look at a number issues and one will be to help develop the assumption set under which the copper network will be characterised,’’ Mr Adcock told the committee.

The committee was chaired by former Communications Minister, Stephen Conroy, who dominated the questioning, referred to documents that were not publicly available, and often pointed fingers at witnesses. Senator Conroy established NBN Co while in government to deliver broadband to more than 90 per cent of Australian premises using a fibre-to-the-premises model. However, the new government come into office with plans to alter this rollout so most premises would receive a broadband upgrade on their existing copper connection rather than a new fibre optic connection.

NBN Co’s head of corporate and commercial Kevin Brown, chief marketing officer Kieran Cooney, and chief technology officer Gary McLaren also appeared before the committee. However, head of strategy and transformation at NBN Co, JB Rousselot, and chief financial officer Robin Payne were not present because they were finalising the strategic review, despite being ordered to attend by the Senate.

NBN Co confirmed its board reviewed and approved the draft strategic review document before it was delivered to Mr Turnbull’s office on December 2.