An NBN Co commitment to begin connecting around 900,000 premises to high-speed internet access within a year has been put on hold by the Federal Government, pending a strategic review of the network.

Communications Minister Malcolm Turnbull and Finance Minister Matthias Cormann - as the shareholder ministers in NBN Co - have issued an interim statement of expectations to the company as a first step in putting the Coalition's stamp on the rollout.

Mr Turnbull says the basic direction is to deliver an NBN "sooner, more affordably for consumers and at less cost to taxpayers".

"In the short-term, the interim statement will see the NBN Co meet its contractual obligations by continuing to roll out fibre to the premises while the company conducts the strategic review of the project." he said.

The Minister has also revealed that NBN Co is proposing to revise down its rollout target for June 30 next year "by almost half" from forecasts made just four months ago.

But, he says, connecting 66,000 premises passed by the fibre network but unable to connect will be the "key priority".

"This includes the majority of apartments, schools and businesses in areas where the fibre network has been rolled out," Mr Turnbull said.

Construction is also set to go ahead in close to another million premises where contracts have either been signed or detailed design work is underway.

However, the future of another 900,000 premises where "only preliminary design work is underway" is now in question.

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"Decisions about actual construction in these areas will be taken after the reviews into the NBN rollout are completed," Mr Turnbull said.

Federal Cabinet will shortly consider a submission for both a strategic review, to be conducted by the NBN Co, and a cost-benefit analysis into the project.

"We expect this period of review will lead to revisions to the timing of the rollout and to updated forecasts," Mr Turnbull said.

"It's important to bear in mind however that the NBN rollout has to date repeatedly missed its targets.

"It is our goal, following the completion of the review and a new corporate plan, to see the NBN Co set realistic rollout targets and then consistently deliver on them."

Turnbull wants less politics, more facts

Mr Turnbull, who was dubbed "Mr Broadband" by Prime Minister Tony Abbott, says he wants the NBN Co to be far more transparent and the issue of a broadband network to be a lot less political.

He says he wants the review to deliver the "plain, unvarnished facts".

"I'm not interested in being given information that people may think will conform to my particular political agenda, whatever they may think that to be," he said.

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"We want sensible, prudent, conservative estimates - not numbers, forecasts that look good at a press conference and fall away a few months later when it's realised they can't be reached.

"There's got to be a lot less politics in this project and a lot more hard-headed, practical business management.

"I mean I know I'm a politician, but my commitment is to make this project as non-political as possible."

The Minister says the in-house review will take 60 days and begin when a new management team at NBN Co is appointed.

Industry groups welcome review

The Australian Industry Group has been a vocal critic of NBN Co's lack of transparency, saying that without a cost benefit analysis it is impossible to know whether Australia is getting good value for money.

Its chief executive, Innes Willox, has welcomed Mr Turnbull's announcement, and concedes it is possible that the best value might be just to proceed with the plan that is already in place.

"That may be an outcome of this review, but at least if that is the outcome there will have been, one would hope, a proper analysis with a lot of expert input to reach that decision and to make that determination," he told PM.

"This may come up with a mix of technologies; it may come up with continuing to push one single technology. Let's just let this process work out."

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Matt Healey, the chairman of the Competitive Carriers' Coalition, which represents internet retailers, says there are many questions the strategic review needs to address.

"We have some clear air over the coming months to continue to roll out NBN and to be able to connect customers, but there is still the work that needs to be done ... to give us clarity around how we're going to use the copper component under the Government's revised NBN," he told PM.

The Government has asked NBN Co to consider using VDSL to bring broadband to smaller communities. VDSL is a technology which makes data flow faster over copper phone lines.

Telstra has struck an $11 billion compensation deal with the Government for access to its old copper network, but that will have to be renegotiated now that that network may be used to deliver broadband to homes.

Some of the copper may also need to be repaired or replaced, and Mr Healey says that will all have to be taken into account.

"It is going to be tricky. Some areas are going to have it and some areas are not, and it's our understanding that it's not really until you start to deploy this network that you understand the full extent of its attributes - that is, how fast the speeds are available over the copper," he said.

Call to resign 'not a criticism'

Meanwhile, Mr Turnbull confirmed he asked the company's seven board directors to resign last week, and all but one have done so.

"That request should not be regarded as any criticism of any of the directors," he said.

"The reason for that was simply to give the Government complete flexibility in remaking the board in light of its new policy agenda.

"Decisions about the board will be taken by the Cabinet in due course."

Mr Turnbull would not name any names of potential replacements.

Former Telstra boss Ziggy Switkowski has been mentioned as a possible contender.