Figures from NBN Co show take-up of the National Broadband Network is behind schedule, with only 4,000 households connected to the high-speed network at the end of 2011.

That figure is well behind an initial target set by the Government to have 35,000 households connected by June last year.

The Opposition's telecommunications spokesman Malcolm Turnbull says it is further evidence of the Government's poor policy execution.

"Well it's pathetic," he said. "It would be comical, this very low take-up, missing their targets by so much.

"They said themselves that they were going to have 35,000 customers connected to the network by June last year, and yet they have only 4,000 connected, only 2,315 of which are connected to the fibre network.

"So this is a shocking shortfall."

NBN Co has attributed the shortfall to delays in the rollout while it waits for Telstra's structural separation approval, which will clear the way for it to use the telco's underground infrastructure.

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But Mr Turnbull says that is a poor excuse.

"The reality is that they have not been able to deliver the connections they said they would," he said.

"There are plenty of areas in Australia where the Telstra infrastructure was either available on a temporary basis if you like, before the final agreements were entered into, or areas where the Telstra infrastructure, such as green fields sites, was not relevant in any case."

Telecommunications analyst Paul Budde says NBN Co is right to wait for the Telstra deal to be approved by the ACCC, which is likely to occur next month.

"That now gives NBN Co the opportunity to roll out the NBN [much more quickly] with the assistance of Telstra," Mr Budde said.

"So, yes, there was a backlog, but because of the contract signed with Telstra, all indications are that that backlog will disappear over 2012, and that the company will be on target for 2012."

"2012 will be the test year," he added.

"If we were to talk about this a year from now and it is still a disappointment, then I think we would have a problem.

"I think that if you could get the 500,000 rollout, roughly that's what they are looking at.

"So if you start looking at 400-500,000 people that are able to get access to it, then I would think you start looking at at least 100,000 people that should be connected to the network around that time."

Prime Minister Julia Gillard has rejected the Opposition's criticism.

"The roll out is proceeding. We did take the time necessary to negotiate with Telstra an appropriate agreement to use its infrastructure because that meant that the NBN could be rolled out more easily using pre-existing infrastructure," Ms Gillard said.