Resurfacing work on the Avonmouth bridge is to blame for gridlock crippling Bristol on Friday afternoons.

Council officials have told their counterparts at the Highways Agency, which is carrying out the work on the M5, that it is having a dramatic effect on city centre traffic.

A Highways Agency official admitted that jams had been expected when the works were planned – but that research predicting the problems was not passed on to other bodies or the public.

A lane has been removed in each direction on the bridge to accommodate a contraflow system while the northbound carriageway is resurfaced. But it is jams on the southbound carriageway, as traffic heads from the Midlands and London to the South West on Friday afternoons, which have caused most disruption.

As the delays increase, drivers leave the M4 and M5 and filter through the city centre to avoid the bridge.

The work started a month ago today and the past four Fridays have seen long afternoon jams on the southbound M32, Bond Street, Temple Way and many main routes through the city. The works are also causing delays for commuters trying to reach Bristol from North Somerset.

Bristol City Council's transport director David Bishop said: "The impact on Fridays in Bristol is dramatic. We are suffering serious gridlock through the afternoon into the evening."

He urged better communications between the Highways Agency's control centre at Avonmouth with the city council's own centre near St James Barton roundabout, which controls city centre traffic.

Mr Bishop said if they could be given "real time" information about the jams on the motorway, then it would help them ease traffic flows.

He was speaking at a meeting of the West of England Partnership – a body which represents the four councils in the former Avon area.

The meeting, in Weston- super-Mare yesterday, was to discuss a range of transport issues.

Justin Davies, managing director of bus operator First in Bristol, described the past few Friday afternoons as "chaotic".

He blamed the roadworks on the Avonmouth Bridge and said it had meant Bristol buses had lost hundreds of running hours.

Mr Davies said he believed electronic signs on the motorway should warn drivers of delays as far back on the M4 as Hungerford.

He also said it was madness that two lanes of the Avon Ring Road were being closed near Downend today, which would add to the chaos.

Chris Jones, regional planning manager for the Highways Agency in the South West, said the delays had turned out to be what they expected.

The agency had carried out research before the work started to see how bad the jams would be.

Mr Jones said they should have passed on this research.

He said they were doing everything they could to minimise the effect of the resurfacing work and supported the idea of real-time dialogue with other control centres.

He told the meeting the fine weather meant the repair work was currently ahead of schedule.

Contractors have taken off the old surface and replacing it with a longer-lasting asphalt which is expected to last at least 20 years.

If work continues ahead of schedule, it should be finished by Christmas.