A former executive at the National Broadband Network has predicted many of the copper wires laid down in the NBN rollout will have to be ripped up and replaced within a decade.

NBN Co has conceded most Australians with fibre-to-the-node (FTTN) will not be able to get top internet speeds.

The Coalition is building the NBN with a mix of technologies — high-speed fibre run to a point in a neighbourhood and copper wires then being used to reach homes and businesses.

But new figures provided to a Senate committee reveal only a quarter of FTTN connections can reach the top speed touted by the Government of 100 megabits per second.

That compares to 100 per cent of customers using fibre to the premises (FTTP), or pay television HFC cables.

Anne Hurley, a former chief executive of the Communications Alliance who worked as head of stakeholder engagement at NBN, said the latest figures highlighted deep-seated flaws in the network’s design.

“It confirms what we’ve been saying from day one: fibre-to-the-node is an obsolete technology, it will never deliver the speeds expected by consumers,” she said.

Ms Hurley warned large swathes of the copper network would have to be ripped up and replaced within five to 10 years.

“If you look around the world other nations are not embracing fibre-to-the-node and copper … so yes, it’s all going to have to go and have to be replaced,” she said.

“The industry needs to pull together a strategy which it can take to the Government and say, ‘Let’s work together on how we can roll out this network, remove antiquated technology, and roll out a network over which we can really operate to provide innovative business services’.”

NBN says average FTTN speeds 10 times faster than ADSL

NBN argues the network will still deliver vastly improved speeds to most Australians.

“Fibre-to-the-node is able to provide average wholesale download speeds of about 70Mbps. This is approximately 10 times faster than average ADSL speeds in Australia,” an NBN spokesperson said.

“NBN’s current plan is to get the network completed by 2020 with all premises able to access at least 25Mbps, and 90 per cent of the fixed-broadband footprint able to access speeds of 50Mbps.”

NBN is continuing to push ahead with the rollout, and had purchased more than 16,000 kilometres of new copper cable by October 22 last year.

But the company has emphasised that most of the cable would be used for connections between existing pillars and new nodes.

Opposition communications spokeswoman Michelle Rowland said the Government’s reliance on copper would be a disaster.

“It’s incredibly disappointing that the Government has arrogantly dismissed the pragmatic pathway recommended by the NBN Joint Parliamentary Standing Committee to deliver more fibre and less copper. This was an opportunity to find some middle ground,” she said.

“Malcolm Turnbull is not interested in solutions, he simply wants to sit back and watch the experience of consumers and the competitiveness of our digital economy languish under his second-rate copper NBN.”

NBN maintains it will be in a good position to upgrade the network in the future because it had “vastly accelerated” the rollout.

“Once we have completed the network build and have eight million premises connected to the network, we will be generating annual revenues of around $5 billion,” it said.

“This will give us a solid revenue base from which to fund future network upgrades for end-users that will enable higher speed services to be delivered without using further government funding.”