Companies in the St Nicholas Street and Market Hill area also said South Norfolk Council should be looking at ways to attract people to the town for longer periods of time.

Oliver Chapman, a partner at TW Gaze estate agent, has written to South Norfolk Council, explaining the potential problems of the Park Road development.

"It will have a very direct effect on the town, which planners may not be aware of," he said.

"I think if they do go ahead with the plan, it will serve only to strengthen the importance of the supermarkets and I think Market Hill, St Nicholas Street and the Yards will suffer."

He also called for the reversal of the traffic system to bring people into the town centre.

But a Norfolk County Council spokesman said: "We are aware there is an issue for the existing town centre but reversing the flow of traffic creates problems for large vehicles ."

He added the regeneration of the town centre and the traffic system were being looked at by the town, district and county councils.

Alan and Gloria Rowe, who own Albright of Diss, in St Nicholas Street, said they were unhappy with the increased parking charges.

They said one hour's free parking does not give people enough time to do their shopping and the higher charges after that detered visitors from spending more time in the town.

"People are going to whizz round and go again to avoid paying parking charges," said Mrs Rowe.

Hilary Whittley, of Whittley Parish estate agent, in Market Hill, said: "The retail businesses I have spoken to, are all concerned this increase in charges is going to affect businesses at this end of town because people can park at the supermarkets for free.

"Are the retailers and businesses at this end of the town to be punished by South Norfolk Council just for being located here?"

Diss mayor Simon Olander said the parking charges were due to be reviewed after six months and urged anyone with concerns to write to the town council.

John Fuller, leader of South Norfolk Council, said: "When we found out that 80 per cent of people would pay nothing by making the first hour free, we thought that was a good way of encouraging people into the town and away from the supermakets."

He said the Park Road development was part of a 20-year local plan that had the potential to make Diss the best market town in Norfolk.

What do you think about the problems raised by the top-end-of-town traders? leave your comments below.