Drivers are being warned to expect delays on the M5 when resurfacing work begins on the northbound carriageway of the Avonmouth Bridge.

The work to waterproof and resurface the bridge will start on September 1 and is set to continue until Christmas. It is the second stage of a two-year programme to resurface the bridge, with the southbound carriageway having been worked on last year.

The work will involve a 50mph speed limit, controlled by speed cameras, and narrow lanes. At times there will be a contraflow. Three lanes will remain open in each direction throughout the work and the cycle path will remain open.

The Highways Agency says the work is weather- dependent and the completion date will depend on the rainfall during the autumn.

Last year's work on the southbound carriageway finished ahead of schedule.

Highways Agency project manager Dave Stock said: "The existing surface was laid during the previous strengthening contract, which started in 1995 and has reached the end of its effective life.

"The southbound carriageway was resurfaced during the autumn of 2008 using a resurfacing material which is able to be machine laid, providing an improved surface finish.

"The northbound carriageway will be surfaced with the same material, which is designed to last longer and give a smoother ride than the existing surface. We will keep three of the four lanes open in each direction to minimise disruption. However, some peak- time delays should be expected and drivers are advised to allow more time for their journeys."

The agency has also announced several major road work projects will be taking place in the coming year to improve the highways network in Bristol.

Schemes include: the replacement of Lawrence Weston overbridge, from December; the replacement of central reservation barriers on the M5 between Almondsbury and Cribbs Causeway, as well as those on the M4 between the A46 and M32 junctions, from January; and work to install the hard shoulder running scheme previously announced by the Government on a five-mile sections of the M4 between the M32 junction and Almondsbury interchange and a seven mile section of the M5 between the Almondsbury and Cribbs Causeway junctions, which will take place over two years between March next year and summer 2012.