New NBN Co chief executive Stephen Rue has lifted the expected cost of the network rollout to $51 billion, with the infrastructure giant planning to raise an extra $2 billion from private sources around 2020.

NBN Co’s funding was previously expected to peak at $49 billion, with a public equity funding commitment of $29.5 billion and a commonwealth loan facility of up to $19.5 billion. Around half the new money will go towards unexpected costs relating to technical issues with its hybrid fibre coaxial (HFC) network late last year, price cuts and network upgrades, while the other $1 billion will be directed to a contingency fund.

NBN Co's new chief executive Stephen Rue said the new expected peak cost of the network would be $51 billion. Credit:Peter Braig

NBN Co in November "paused" connections to the NBN via pay-TV cables while it addressed dropouts being experienced by a “minority” of the 370,000 customers already connected. About 3 million premises will be connected using HFC when the rollout is complete. This delay of several months cost NBN Co about $700 million, with “additional optimisation” expenses on the HFC network totalling $200 million.

A further $700 million was due to a recent wholesale pricing change, designed to encourage Australians to pay for faster plans by reducing the cost of the 50Mbps product. This has seen the take-up of faster plans double in recent months.