Prime Minister Malcolm Turnbull has admitted it was a "big mistake" to set up a new company to build the National Broadband Network, adding that Labor left the Coalition a "calamitous train wreck".

Key points: Malcolm Turnbull was the minister responsible for the NBN before he became Prime Minister

Malcolm Turnbull was the minister responsible for the NBN before he became Prime Minister He deflected some questions this morning by saying previous Labor governments were to blame for botched rollout

He deflected some questions this morning by saying previous Labor governments were to blame for botched rollout He admits there's a "reasonable question mark" over whether or not NBN Co will ever make a profit

Mr Turnbull was questioned about the NBN this morning after Four Corners reported the troubled rollout was creating a digital divide across Australia, with some households saddled with older technology such as copper phone wire and pay TV cables, and unable to access the high speeds they are paying for.

The Telecommunications Industry Ombudsman also revealed an almost 160 per cent increase in NBN complaints over the past financial year.

NBN chief executive Bill Morrow said those complaints needed to be kept in perspective given the difficulty of the rollout.

To make this point, the NBN Co revealed the more expensive FTTP connections in each state and territory, including one installation close to $90,000 at a lawn bowls club in Tasmania.

Mr Turnbull conceded there were many problems with the NBN, but said the Government was doing the best it could in the situation.

"As I often used to say, in the words of the Irish barman when asked for directions to Dublin, 'If I were you I wouldn't be starting from here'," Mr Turnbull said.

"No-one would've wanted to start from where Labor left us, so we have done the best we can getting that project on track."

Mr Turnbull, who was communications minister before becoming Prime Minister, said many of the problems were caused by the way the project was designed.

A government-owned corporation was established to build the network.

"The NBN was a calamitous train wreck of a project when we came into government in 2013," Mr Turnbull said.

"Kevin Rudd said this was going to be fantastically commercial and the public would be lining up to invests in it. That's nonsense."

Labor's communications spokeswoman Michelle Rowland hit back at the Prime Minister's criticisms, saying the Coalition promised something they could not deliver.

"This is absolute rubbish coming from a government which said they would deliver the NBN by 2016 for $29.5 billion. It's now blown out to $50 billion and 2016 came and went," she said.

"When Labor came to office in 2007 Australia was a broadband backwater. We needed to do something then we knew the market would continue to fail.

"Every person in rural and regional Australia should know Malcolm Turnbull thinks its a mistake for you to participate in the digital economy."

Mr Turnbull said Australia should have followed New Zealand's model.

"They basically ensured the incumbent telco, the Telstra equivalent, split its network operations away from its retail operations. And then that network company in effect became the NBN," he said.

"The virtue of that was you actually had a business that knew what it was doing, that was up and running, that had 100 years of experience getting on with the job."

Mr Morrow said changing technology, expensive fit-outs and competition meant NBN Co may never make a profit.

Mr Turnbull said the company was expected to deliver a 3 per cent return on investment, and while not impressive, the result would be worse if the Government carried out Labor's plan to connect fibre to the premises.

"It is enough to keep it on the Government's balance sheet, as a government asset, but it certainly isn't a commercial return that the stock market would respect," he said.

"It would have taken another eight years to complete and another $30 billion, so if you think the commercial criteria are challenging now, imagine what they'd be if you loaded another $30 billion of cost onto it."