Government yesterday defended the figures it gave to explain some of the cost overruns run up during the building of the new cruise ship pier at Dockyard.

Some of the $25 million increase in the cost of the project from the initial Total Allocated Funding (TAF) of $35 million, was attributed to ensuring the work caused no harm to the dolphins held in captivity at Dockyard.

In June, in response to questions from Opposition Senate Leader Michael Dunkley, Government detailed how up to $10.3 million of extra costs had been attributed to "delays and dolphin mitigation".

Principals of both general contractor Correia Construction and subcontractor Norwalk Marine International described the Ministry of Tourism and Transport's figures as inaccurate in interviews with this newspaper.

For example, Correia director Dennis Correia told this newspaper that the $4.4 million claimed by Government to be the cost of a change of construction method to pre-cast concrete from cast in-situ concrete was incorrect, as the two methods' costs worked out to be similar. Asked whether it intended to release an accurate breakdown of costs as a matter of public record, a Ministry of Tourism and Transport spokeswoman said: "The information previously released is in accordance with Ministry records with respect to the 'dolphin mitigation measures'."

Asked what financial controls were in place on the project, she said: "Monthly valuations were required. These valuations were reviewed and recommended for payment by an independent project manager. All calculations were verified by the Ministry."

Correia Construction told this newspaper last week its costs had reached $55.8 million of the $60 million TAF. Government yesterday described the additional $4 million costs as "project management/engineering, environmental impact statements, and architectural fees".

The spokeswoman also described the changes in design to the thruster wall, which acts as a shield against sediment stirred up by cruise ship propellers. Mr. Correia said the thruster wall had been "redesigned four times".

The spokeswoman said: "The original thruster wall was based on a schematic design prepared by the original design consultant. After meetings with Marine and Ports pilots, the design was revised to include a longer thruster wall to accommodate ships berthing in either direction. In addition, after a series of winter storms and the threat of a hurricane this summer, it was decided to review the design again. The revisions included strengthening the wall based on the information received during real-world sea conditions during construction.

"The Ministry supported the recommendations made by the independent project manager (Entech) and the Department of Marine and Ports Pilot Services. The thruster design is based on the Voyager class ship, the same ship coming to Dockyard today."

She said there were no plans to bring in eventual larger ships, such as the Genesis. The thruster wall however, has yet to be finally installed at the dock.

The spokeswoman said: "The delay is due to the requirement to have calm seas to construct the wall. This could not be done in the winter, nor during the season when ships are in port. Thus, the decision to construct the wall now, before the winter begins. We don't anticipate additional costs. The revisions to the wall cost approximately $2 million over the original estimate. This is due to the longer and more reinforced wall, not in the delay of constructing it."

Asked whether the delay has had a detrimental impact on the dolphins, due to ship sediment over the last several months, she said: "No, the impact of thrusters has been monitored."