Health bosses in South Gloucestershire are having to look at their sums for the refurbishment of Cossham Hospital so they can find ways of cutting £2.5 million from projected costs.

The regional arm of the Department of Health, NHS South West, has allocated £19 million for the project to modernise the site as a community health centre.

But so far plans for the scheme have come in at £21.56 million.

Project leaders are working with designers to find ways to reduce the cost of the scheme.

Because Cossham is more than 100 years old and a listed building there are more challenges in terms of the design and the materials that can be used.

South Gloucestershire Primary Care Trust (PCT), which is heading up the project, will be working with the planners and English Heritage on cost-cutting options.

Plans to modernise the hospital will turn it into a community health centre and a hub of services for about 126,000 people in Kingswood and the surrounding area.

Proposals had been made to close the listed building to patients under the Bristol Health Services Plan because it needed extensive works – at great expense – to provide modern healthcare.

But overwhelming public support meant NBT consulted again and it was decided to spend the millions needed to bring the 100-year-old hospital up to date.

When the site opens after the work it will provide diagnostic tests, including X-rays, MRI and CT scans, a birthing centre and a renal dialysis unit so patients will not have to travel to Southmead for the bulk of their health needs.

Health bosses are optimistic about the project and are determined to get all the relevant approvals in place for work to start on the site by autumn next year.

A draft business case for the refurbished hospital has been passed by South Gloucestershire PCT and will be passed onto the strategic health authority in December, which will make a final formal decision on the plans in April.

It is hoped that planning permission and approval from English Heritage and NHS South West will happen at roughly the same time.

Project leader for the PCT, Roger Pedley, said: "We will look at the design, materials and other costs again to see if there are other ways to design less expensively.

"Projects are never straightforward but we are feeling very confident about it.

"We know this is important for local people and know it is important in the way we provide local health services."

Cossham is in the process of being transferred from North Bristol NHS Trust, which currently runs the hospital, to South Gloucestershire PCT, who will commission the services provided at the site.