The cost of a swimming centre refurbishment project has risen to accommodate new multi-functional rooms.

The project at Hitchin Swimming Centre on Fishponds Road, which includes Archers Health and Fitness Club, will now cost £1.1million – an increase of £380,000 from the original budget.

The money is being used to create an extension at the centre, which is managed by Stevenage Leisure Limited (SLL) on behalf of North Herts District Council (NHDC), which owns the facility.

Cllr David Leal-Bennett, who represents the Hitchin Highbury ward, said: “The whole point of an Invest to Save scheme is that the capital plus interest is repaid over an agreed period. The project has gone over budget by 30%, so it is questionable that the original business case was sufficiently robust.

“This is tax payers’ money and officers must ensure that projects are sustainable with a detailed financial model. I will be requesting detailed financial information for scrutiny which should be publicly available.”

Cllr Ian Knighton, portfolio holder for leisure at NHDC, said: “Providing the new facilities will help ensure we meet both the current and future needs of the local community, and will also help secure the long-term financial viability of the site for council tax payers.

“There has been an increase to the original budget of £720,000, but by negotiating an extension to the contract with SLL, which manage the facility on the council’s behalf, the council will actually reduce the operating costs of the facility by £1.6m. SLL committing to reducing their management fee to the council over the next 10 years will mean the council is reimbursed for its investment in these new facilities.”

The increase falls within limits previously approved by the cabinet.