Telstra has chosen not to tender for the $56 billion national broadband network's biggest construction contracts, which will connect millions of homes and businesses using the Coalition's preferred fibre-to-the-node technology.

Fibre-to-the-node and fibre-to-the-basement reuse the existing copper network and will become the main phone and internet line for 4.5 million homes and businesses by 2020, which represents 38 per cent of the total NBN footprint. Labor's plan was to connect 93 per cent of premises directly with faster and more expensive fibre-optic cabling.

Telstra and NBN had originally hoped Australia's biggest phone and internet provider could help install the new technology, which relies on the copper phone network that has long been owned and managed by Telstra. Australia's first fibre-to-the-node services were built by Telstra and launched last week in Belmont, NSW.

But Telstra walked away from the first round of construction contracts in June after its alternative non-conforming proposal was rejected and a spokesman for NBN said it chose not to compete in the second round, which covers all major contracts for the remaining States and Territories.

NBN on Monday will announce the winners of the last major contracts to connect premises across Australia using fibre-based technologies apart from hybrid fibre-coaxial networks.