It estimates the junction upgrade at Tredgar will cost around £30m to deliver.

The upgrade would see construction of an elongated gyratory to the south of the M4 with a dedicated through link for eastbound traffic from the M4 and A48 towards the A48 SDR.

The improvement to Junction 28 retains the M4 underbridges but requires the demolition of the M4 westbound on-slip underbridge over the A48 eastbound.

Existing junction layout

Planned new layout

There will also be improvement to nearby roundabouts at Bassaleg and Pont Ebbw roundabouts to help cut congestion.

Expressions of interest are needed by 28 March with tenders expected to be invited from five contractors at the end of April.

PQQs are available on the e-tender Wales portal using the search PQQ/ITT code pqq_31214.