Work starts this month on a scheme to revamp Oxford’s High Street.

The improvements, costing £3m, could result in months of disruption for bus-users and traders, with work starting on June 22 and expected to continue until April.

Work is also due to begin in Queen Street on July 19, which will see the pedestrianisation of most of the city centre over the next five years.

County Hall has defended the decision to allow both schemes to get under way at the same time and is now in talks with bus companies to minimise the disruption.

Steve Howell, county council head of transport, said: “There will obviously be some disruption, especially to bus users. We believe that Queen Street and High Street work can happen at the same time. It must be remembered that neither of these routes are open to general traffic anyway.”

But the plans for the High Street were condemned as “a wasted opportunity” by traders, who accused Oxfordshire County Council of ignoring their views.

They said the city centre was now facing nearly a year of disruption for a scheme that amounted to little more than repairing road damage caused by the weight of 2,500 buses a day.

High Street traders and colleges had called for work to be suspended to allow a more ambitious scheme to be developed, creating wider pavements with quality stone.

Resurfacing work will take place between Turl Street and Longwall Street, with a pause from the end of November to the New Year to help traders over Christmas.

The work will result in the closures of roads such as Queen’s Lane, Merton Street and King Edward Street at times. But the council said the work should be completed without bus services having to be diverted.

County Hall said that as well as resurfacing the road, it will “declutter” a large section of the street, with unnecessary signage and white lines removed.

Mr Howell added: “We will also be making some targeted alterations to benefit pedestrians and cyclists.

“It will mean that no further work will be required on the route for 20 years or more.”

But Jeremy Mogford, chairman of the High Street Association, said: “We are bitterly disappointed that the council has not taken on board any of our suggestions. This is just a resurfacing job with a bit of decluttering as window dressing.

“This work will nevertheless have a major impact on businesses, bringing heavy congestion. The buses are not to be diverted when the work is going on, so there will be big queues.”

Traders and colleges commissioned their own report by urban designers Alan Baxter Associates, which said the council’s plans would transform the city’s spine into “a mediocre” public space, wasting a one-off chance to deliver what “this nationally significant street so desperately needs”.

The county council is proposing to pedestrianise George Street and Magdalen Street next year, with improvements to Broad Street to quickly follow. Frideswide Square should be redesigned in 2011.