NEWPORT motorists could face evening traffic congestion as a busy part of the M4 is regularly closed by roadworks from tomorrow.

The Brynglas Tunnels will be closed either on the westbound or eastbound carriageway on several days throughout 2008 as workers carry out routine maintenance.

A 40 mph speed limit will be imposed on whichever carriageway is open during the evening hours of 8pm to 6am.

The road closures will affect the section around half a kilometre to the west of the tunnels to more than 800 metres past the eastern side of the tunnel.

Work on the motorway begins tomorrow and will take place every Friday and Saturday night for the rest of the month.

Most Friday and Saturday nights will be affected throughout 2008, except during August when no road closures will be in place.

The length of the eastbound entry slip road, which connects the A4051 roundabout with the main eastbound carriageway of the motorway at junction 26, will also be closed at times.

Eastbound traffic will be diverted off the A4051 roundabout along the westbound on slip road, along the M4 to junction 27 before leaving the motorway via the westbound off slip road and rejoining the M4 via the junction 27 eastbound on slip road.

When the westbound slip road at junction 26 is closed, vehicles wishing to leave the motorway at junction 26 can continue on the motorway to junction 27 before exiting and rejoining the motorway on the eastbound entry slip road.