Councillor Phil Blight said the council had a verbal agreement with Optus to install underground cabling as part of the $3.75 million upgrade of Gymea shopping centre at no cost to the council.

"But Optus has reneged," he said.

An Optus spokesman said the company had met with the council on several occasions and it had been clearly communicated that all associated costs of the relocation would be the responsibility of the council.

The council is now seeking legal advice on the matter and will continue discussions with Optus.

"In the meantime, the council is committed to completing the upgrade of Gymea shopping centre on time," a council spokeswoman said.

A council spokesman said discussions had been held with Optus representatives to relocate its aerial cables in Gymea shopping centre to underground conduits.

"The understanding was council would bear the cost of installing the underground conduits and that Optus would fund the relocation of its aerial cables to the underground conduits provided," the report stated.

"Council has had the conduit installed in a common trench with underground power conduits awaiting the relocation of the Optus aerial cables. Optus has now provided a quotation of $110,000 (excluding GST) for their undergrounding."

Who do you think should pay the bill?