An off-duty Ausgrid worker noticed the problem at the Water's Edge construction site on the corner of The Esplanade and King Street, Warners Bay, on July 23.

The high-voltage power lines carry 11,000 volts of electricity.

The $80million project, expected to be completed next year, is being built and developed by Canberra firm Bloc.

It will house 112 one, two and three-bedroom apartments across two buildings, with retail and commercial space on the ground floor, and 200 car spaces.

An Ausgrid spokeswoman said the power line issue triggered urgent action due to fears for workers' safety.

"An Ausgrid representative immediately visited the site and after confirming the hoarding was not maintaining safe working distances, an Ausgrid team worked that night to isolate the high-voltage mains and make the building site safe...," she said.

"Work has continued, following Ausgrid's actions to make the mains safe by isolating and earthing."

Ausgrid had a worker stationed at the building site, which was a former BP service station, to ensure all workers were aware of the high-voltage mains and the controls in place to ensure the site was safe.

Workers had to sign a permit to confirm they understood the safety controls.

It's understood there are also low-voltage, 415 volt, mains in the area, but they had been safely covered to allow building to continue.

A SafeWork NSW spokeswoman said Bloc contacted its office on July 24, the day after Ausgrid identified the problem, to enquire about the installation of hoarding.

"Susequently Ausgrid, the energy supply authority, disconnected the powerlines and the principal contractor repositioned the hoarding," she said.

"SafeWork is liaising with the principal contractor and Ausgrid to ensure there is compliance with NSW Work Health and Safety legislation in regard to the proximity of power lines to the construction site."

It's understood further inspections will take place at the site over the coming months.

It has been a difficult few weeks for Bloc. Last month a burst water main caused damage at The Verve Residences, two identical towers that have been constructed on King Street, Newcastle, over the past two years.

A tested pressure pipe burst on July 14 and sent water running through the southern tower, causing damage to floors below. The building was having the final touches added in recent weeks in preparation for the first residents to move in.

Bloc did not respond to requests for comment.

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