It has become a rare sight to see water shoot out of the Captain Cook Memorial Jet the diver was working on, which hit another setback as the National Capital Authority waited several months for its new cables.

A specialist diver laid the new low-and-high-voltage cabling on Tuesday morning, which added more than $50,000 onto the $2.7 million repair job that has seen the fountain dormant since June 2015.

Earlier this year, the NCA decided to abandon asbestos-encased cabling that was powering the jet and leave them buried on the advice of asbestos specialists.

The diver was hired to help connect the cabling that travels from the jet to the underground pump house with the newly refurbished pumps and then to the new transformer, which was installed last week, NCA chief executive Malcolm Snow said.

"It is pretty expensive cabling, we had to wait a number of months to get it supplied," he said.

"So the asbestos problem put us back, that has now been resolved, but then there was the wait time in ordering the cables."

Another hiccup was caused when it was discovered the substation transformer at Regatta Point was outdated, and the high-volatage cables could not be connected without upgrades.

Mr Snow said the uncertainty over who would pay for the new substation transformer had been resolved, after previously saying the authority wanted ActewAGL to share the cost of the substation upgrade.

"We have come to an agreement with Actew, who have certainly come to the table and taken the opportunity to look at their assets," he said.

"While they also have some assets in the actual sub station itself, we have an agreement for things that we are responsible for, in particular the transformer which only supplies the jet so that's clearly our responsibility."

He said he could not provide further details about which parts of the refurbishment Actew had agreed to pay for.

Mr Snow said the overall refurbishment remained within the project's budget and was confident there would be no further hiccups.

"It is an iconic feature here in Canberra and we are determined to get it up and running," he said.