Bus passengers are being warned of disruption to services next week when a key roundabout on Norwich's busy ring road is closed in all directions for at least five days.

The Dereham Road/Sweet Briar Road roundabout will be shut from Monday, May 28, during half-term week, so the revamped roundabout can be resurfaced.

It will mean traffic will not be able to cross the roundabout, affecting the tens of thousands of motorists who use the ring road and Dereham Road, as well as bus users.

Due to the roadworks First Norfolk and Suffolk is making significant changes to its red line 23/23A, 24/24A buses to Costessey and Queens Hills and orange line 21/22 buses to West Earlham and Bowthorpe. There will also be a minor impact to blue line 26 buses.

A statement on the First website states: 'We have taken the decision to split the orange line and red line services in the city centre because this will minimise the significant impact of the road closure, particularly in the east and north of the city.

'Beyond the changes detailed, at this stage it is uncertain what impact this closure will have in any great detail, and what knock-on effects there will be to other services across the city.'

Normal timetables will run as usual on Bank Holiday Monday (May 28) but congestion due to the road closure may impact journey and departure times

Red line

Daytime buses Tuesday to Friday

Buses between Thorpe St Andrew and the city centre will operate to normal timetable throughout the closure. But buses will terminate on St Stephens Street and will depart from a temporary stop at the bottom of Surrey Street on outbound journeys towards Thorpe St Andrew.

Buses between Heartsease and the city centre will operate to a slightly different timetable throughout the closure, running every 20 minutes rather than every 15 minutes. Buses will terminate on St Stephens Street and will depart from a temporary stop at the bottom of Surrey Street for journeys towards Heartsease.

Buses between Costessey and the city centre will run to a much reduced timetable and will operate the following routes:

• 23: City Centre (Theatre Street), Dereham Road, Bowthorpe Road, Earlham Green Lane, Larkman Lane, Dereham Road to Breckland Road, Grove Avenue, East Hills Road, Dereham Road, Longwater Sainsburys, Queens Hills.

• 23A: City Centre (Theatre Street), Dereham Road, Bowthorpe Road, Earlham Green Lane, Larkman Lane, Dereham Road, Norwich Road, Town House Road, Longwater Lane, Dereham Road, Longwater Sainsburys and Queens Hills.

In the city centre, all buses will only serve Theatre Street and buses will terminate at the first roundabout in Queens Hills and will not operate via Kestrel Avenue. 24 and 24A routes are replaced by 23 and 23A.

Evening buses

First will aim to operate all evening buses on routes 23 and 23A to normal routes and timetables but will diverting around the affected area.

Orange line

Daytime buses Tuesday to Friday

Buses between Old Catton and the city centre will operate a temporary timetable, with buses up to every 15 minutes. But there will be a temporary timetable in place and buses will terminate on St Stephens Street. They will depart from Red Lion Street towards Old Catton as usual.

Buses between Bowthorpe and the city centre will operate to a reduced frequency of up to every 20 minutes, and will follow a temporary timetable. There will be one bus per hour between Bowthorpe and the UEA (22), and two buses per hour between Bowthorpe and the Norfolk and Norwich University Hospital (21).

In the city centre, buses will serve the Theatre Street stop only.

Evening buses

First will aim to operate all evening buses to normal timetables, although congestion due to the road closure may impact on journey and departure times.

Blue line

Daytime buses - Tuesday to Friday

Buses from the train station to the University of East Anlgia will run every 20 minutes with all journeys extending to the Norfolk and Norwich University Hospital. This is to allow extra time as the route is likely to be affected by traffic diverted away from the Guardian Road roundabout area.

Evening buses

First aim to operate all evening buses to normal timetables, although congestion due to the road closure may impact on journey and departure times.

• For full information and timetables visit the First website.

Konectbus has also warned of disruption to route five which will be diverted via Larkman Lane, Earlham Green Lane and Bowthorpe Road (in both directions), Larkman Lane/Aldi, Cadge Road, Whistlefish Court, Winchcomb Road and Holly Drive. The company has confirmed bus stops will not be served during this period and passengers should walk to their nearest bus stop.