The Australian has confirmed that under the $11 billion deal between the government, NBN Co and Telstra, Telstra could face penalties if it delays the rollout of the $37.4bn project, while a leading asbestos lawyer warned that legal liability could also fall back to the commonwealth.

"Telstra must meet timetable and fitness standards for providing access to its infrastructure for NBN Co," a Telstra spokeswoman said.

"If we don't meet these obligations, penalties may be imposed. However, we're not concerned with where things are at this stage. We are ahead of schedule."

The NBN Co has also put penalties for delays into its construction contracts.

Late yesterday, Jane McDermott, Maurice Blackburn principal in the asbestos and dust diseases practice, said the commonwealth and its workers compensation scheme, Comcare, could also face liability.

"We know Telstra and the commonwealth are well aware what these pits are constructed out of," Ms McDermott told The Australian.

"As there is no safe level of asbestos exposure, it's unforeseen the sort of liability that Telstra, the NBN Co and the commonwealth may have on account of this, that the taxpayer will have.

"What's urgently needed is an understanding of Telstra and NBN Co's public liability insurance situation, as this would be what people should need to claim on down the track, should they claim on something asbestos-related."

Last night, the Coalition echoed warnings that the NBN Co could be legally exposed, as well as Telstra, and that the asbestos issue had not been expressly addressed in the NBN Co's corporate plan.

"Telstra is obviously legally liable for what it does in its own pits," opposition communications spokesman Malcolm Turnbull said.

"But you've got to remember, there is a lot of work being done in those pits by NBN contractors as well. It's in the nature of the NBN Co rollout that a lot of these pits are having to be replaced and the replacements are being done by NBN Co. It's not just a Telstra issue. It certainly exposes the NBN Co."

Mr Turnbull said the issue of asbestos would need to be addressed and the Coalition's alternative fibre-to-the-node model would raise fewer asbestos problems.

"It's just another aspect of the argument for not taking the fibre into every house; you are not disturbing all that old infrastructure."

Ms McDermott, who has been litigating asbestos claims for 12 years, said employers generally had a duty of care to provide a safe place of work.

The issue of public liability insurance was relevant to bystander exposures and workers or contractors who were not viewed as employees, she said.

While it was too soon to know whether the exposures had caused damage, if people "were to develop something down the track" they could sue, she said.

NBN Co has recently put out tenders for a request for capability for contractors to remove asbestos.

NBN Co spokesman Andrew Sholl said the health and safety of communities and workers was "our No 1 priority", but he declined to comment on whether Telstra could face penalties under the $11bn deal because "we don't comment on details of commercial contracts".