Winchester residents and traders are facing a severe case of dj vu as more disruptions and road closures look set to hit the city centre.

The proposal is part of Southern Water's £750m environmental and water quality improvement schemes in Kent, Sussex, Hampshire and the Isle of Wight that started in 2005 and are due to finish in 2010.

Work is likely to begin in Winchester city centre in 2008 and will be carried out by 4Delivery, a consortium comprising United Utilities, Costain and MWH.

Graham Love, of the City Centre Partnership, said: "If sewers and water pipes are going to be replaced, then the level of work will be greater than we have experienced so far for the gas works."

Some businesses claim their profits have dropped by as much as 60 per cent during the gas main repairs that will end in June, after around 20 weeks of city centre chaos, and the news that more work is in store has angered traders.

Jason Moore, manager of the Charles Baynham Butcher shop on the High Street, said: "They should have done it at the same time as the gas works. It might be essential work, but for a lot of businesses that rely on passing trade it must be very hard on them. We are OK because people come to us either way.

"But it's unbelievable how quiet it is out there. I feel the work drives people away and they get into the habit of using shops in another area."

Katie Allan, director of the clothing shop Debut, said she might be forced to relocate her business if the improvements last as long as the gas works have.

"I don't think our business can survive this type of work again. We really can't sustain another period like this.

A spokesman for Southern Water said: "We are planning an environmental improvement scheme in the city centre to help reduce incidents of flooding to properties.

"Our contractors, 4Delivery, will be carrying out investigations to decide the best way to carry out this vital work while causing as little disruption as possible.

We expect to complete this work before 2010 to bring about these essential improvements to the area and will keep everyone informed as we move forward with the scheme.

"We will be doing our investigations soon and until they have been done we won't be able to say how big it might or might not be. It's very much early days at the moment."

A spokesman for the city council said: "As in the past, we will always work with local businesses, the county council and contractors to keep any disruption to a minimum.

"We need to find out more details about what is going to happen before we can do anything else."