The Turnbull government’s campaign to defend Bennelong has been dealt a blow after NBN Co revealed it would delay the rollout of the main technology being used to connect homes and businesses in the electorate.

Most homes and businesses in Liberal MP John Alexander’s seat in Sydney’s north-west are slated to connect to the NBN via the Hybrid Fibre Coaxial (HFC) technology, which utilises existing pay TV cables.

Amid growing frustration about the rollout nationally, Labor’s candidate, former NSW premier Kristina Keneally, has sought to make the NBN a key campaign issue for the byelection to be held on December 16.

And in a case of bad timing for the government, NBN Co revealed on Monday the nationwide HFC rollout would be delayed, a setback that means tens of thousands voters in Bennelong will now have to wait up to nine months longer for the NBN.

Labor claims more than 48,000 premises in the Bennelong electorate are slated to use the technology, which critics have argued is prone to dropouts and slow internet speeds. That includes the suburbs of Ryde, Epping, Marsfield, Macquarie Park and Putney.

Most of the Bennelong electorate will be connected using HFC.

A group of more than 23,100 Bennelong homes and businesses were slated to be fit for service between January and March next year, before NBN Co chief executive Bill Morrow announced a halt to the HFC rollout on Monday.

Mr Morrow conceded the company had received more complaints from customers using HFC than other technologies, though he said the “specific number of dropouts is quite small”.

“This will result in a six- to nine-month average delay for those people that have yet to connect to the NBN network over HFC,” he said.

NBN CEO Bill Morrow revealed the delay on Monday. Photo: AAP

Labor seized on the announcement on Monday, which was initially buried in a press release from the company.

“It’s a disgrace. This means that families and businesses in Bennelong will have to wait longer for a second rate broadband service they have to pay more for,” said Ms Keneally.

She said only one in 10 homes in Bennelong were connected to the NBN.

There is growing frustration about the rollout of the NBN. Photo: AAP

But the Coalition hit back, saying Labor “didn’t connect a single house in Bennelong to the NBN” while in office.

Nationally, almost three million premises are slated to access the NBN using the Hybrid Fibre Coaxial (HFC) connections.

NBN Co said on Monday nearly one million premises could now access the NBN via HFC and 370,000 were already connected.

Communication Minister Mitch Fifield and Mr Alexander did not respond to a request for comment.

The HFC technology was introduced in 2015 as part of the NBN’s multi-technology mix overhaul overseen by the then communications minister Malcolm Turnbull.

An election issue

Mr Alexander holds Bennelong by nearly 10 per cent but recent polls have suggested the contest will be much closer.

West Ryde business owner Stefan Sojka told The New Daily the NBN rollout was a point of frustration for many local businesses and he predicted it would be one factor for voters in Bennelong.

“We’re hearing a lot about it,” said Mr Sojka, a board member of the local chamber of commerce. “It’s just a general feeling that we’re lagging.”

Mr Sojka, who runs a recording studio, said the NBN was particularly crucial for small startups in the Macquarie Park business hub.

“One of my associates runs a media business and they’re constantly needing to upload and download very large files,” he said.

“They’re quite often staying back late and having to apologise to clients (due to poor internet).”