NBN Co announced on Thursday afternoon it was revising down its forecast for the rollout of fibre optic cable from the June 2013 target of 341,000 premises to between 190,000 and 220,000 premises. It is the third time the target has been revised.

NBN Co chief executive, Mike Quigley, said: "We are accountable for the delay and are disappointed it has occurred.

However, he laid the blamed squarely with contractors who he said were responsible for meeting the targets.

"The problem is we are just not seeing the ramp up of construction workers on the ground that would be needed to deliver these targets," Mr Quigley said.

On Wednesday, during question time, the opposition asked Communications Minister Stephen Conroy if he was using carrier pigeons to seek updated information about connections from NBN Co.

Mr Conroy was being grilled on whether NBN Co would achieve is June 30 targets.

Senator Conroy said there had been ''workforce mobilisation issues'' in Western Australia, South Australia and Northern Territory.

He said NBN Co had taken control of construction of the NBN in the NT because contractor Syntheo, a joint venture between Service Stream and Lend Lease, had failed to meet roll out targets.

Syntheo, told the Australian Securities Exchange on Wednesday it had "pulled out" of construction in the Northern Territory ahead of an expected announcement on significant delays, according to the Australian Financial Review. The company is also responsible for all construction work in Western Australia and South Australia, under a separate contract.

The NBN Co will now take over the rollout in the Northern Territory including training and employing "additional specialist telecoms workers ('fibre splicers"') to help recover lost time in the rollout of the network".

Last month, Mr Quigley blamed Syntheo for NBN Co needing to lower its forecast of existing premises to be passed by optic fibre cable this June to 286,000. There were 52,014 premises passed at the end of 2012.

Senator Conroy said the information about the connections was detailed and complex and involved multiple construction partners. ''It's not simply a question of NBN Co pushing a button,'' he said. On Wednesday he said 40,000 Australians were using the NBN.

Meanwhile, opposition spokesman for communications, Malcolm Turnbull is upping the ante on the Opposition's alternative plans.

He said Australians would have faster and cheaper broadband under the coalition and promised to release the coalition's NBN policy "months before the election".

Last week a new report by a consultancy group, outlined the policy options for the coalition should it win the federal election in the interest of "informing and invigorating" the policy debate.  The report by Allen & Overy and Venture Consulting reiterated major elements of the NBN, "not just the total project", must be subject to a clear cost and benefit analysis. And among other things, it said existing assets that can be effectively deployed, should be made available by the government at low cost, not be paid to be shut down, as is the case with the Telstra copper network.

The NBN Co has said its remit is to deliver fibre to 93 per cent of premises, as asked by the government, not to explore alternative existing methods of delivery.

The report also recommended the role of the NBN Co be reviewed to perhaps act more as a coordinating agency, than a builder, contracting out design, build and maintenance responsibilities to third parties.

NBN Co also announced the replacement of chairman Harrison Young with Siobhan McKenna as of today. Mr Young resigned today after three years as chairman. Ms McKenna is a managing partner of Ten Network.

with APP

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