A Senate committee has been told NBN Co has now purchased 21,078km of new copper, after adding a further 4478km to its existing stockpile since October 2017.

"With 21 million metres of copper at their disposal, the Liberals have bought enough to wrap around Australia one and a half times," Labor communications spokeswoman Michelle Rowland told AAP.

"While Malcolm Turnbull has access to top speeds of 100 Mbps at his Point Piper residence, three-in-four Australians on fibre-to-the-node cannot achieve those speeds."

Labor has called on the government to abandon the copper rollout wherever feasible, and at a minimum take fibre to the curb.

Copper is used to make the connection between the node cabinets and the existing pillars, but the connection from the telephone exchange is fibre.

NBN says fibre-to-the-node is capable of average wholesale download speeds of about 70Mbps, 10 times faster than ADSL speeds.

Australian Associated Press