Lake Macquarie City Council has expressed frustration at the news.

It is blaming NBN Co for a "lack of communication" during the street beautification works. It's a claim NBN Co has refuted. Council said it anticipated the NBN roll-out years ago, during the design of its streetscape works.

Council said it laid conduit between the Telstra service pits along The Boulevarde in an attempt to accommodate the future needs of NBN infrastructure. But NBN Co said excavation would still be required. Works started on Sunday. The council's built and natural assets director David Hughes said council was disappointed with the previous lack of communication from NBN and its contractors.

"We attempted to consult with NBN during the design phase and prior to construction of The Boulevarde project about the requirements to prevent this situation from occurring, but received no correspondence from them during this time," Mr Hughes said.

A spokesperson for NBN Co responded to the claim.

"As part of our standard processes NBN Co always engages with local councils on the design and planning ahead of construction in a region and we will continue to consult with the local council as construction begins in Toronto," the spokesperson said.

The good news, if it can be called that, is the situation could have been much worse - about 230 metres worse.

"Where possible, NBN will use existing infrastructure and in this case we will use the existing conduit already in place but will need to carry out additional work," the spokesperson said.

The council's installation of the conduit had reduced the excavation required by around 230 lineal metres, Mr Hughes said.

"Council has invested significantly in beautification works for The Boulevarde, and this excavation will not only affect the completed works, but will disturb local business owners and the Toronto community, who have enjoyed the improved amenities and landscaping," he said.

Council said NBN Co contractor, Visionstream, would begin excavation works on the northern side of The Boulevarde from this Sunday, May 26, before moving to the southern side of the street.

"We will be providing NBN with a quote to complete remediation works for the southern side of The Boulevarde, but it will be up to NBN to accept our advice and support," Mr Hughes said.

NBN Co said there "could be some minor disruption" for local businesses but it would also foot the bill for the repair works, they said.

"We will continue to work with the local council to help arrange permanent reinstatement for all pavement surfaces, which will be returned to their original condition and NBN will cover the cost of this," they said.

"Construction is set to last for four to six weeks and we apologise in advance for any inconvenience this may cause to local residents or businesses as we carry out these important works."

The NBN roll-out aims to give Australians access to fast internet services. Council would continue to work with Visionstream on the roll-out of the NBN "with a focus on ensuring that the current high-quality finish" of The Boulevarde streetscape was maintained, Mr Hughes said.

Council's $4-million works, carried out as part of the Toronto Streetscape Master Plan, were completed in July.