Media playback is unsupported on your device Media caption Heads of the Valleys dualling "has been hell'

The completion date for widening parts of a major road - which is already £54m over budget - is being reviewed.

Work on the A465 Heads of the Valleys road from Brynmawr in Blaenau Gwent to Gilwern, Monmouthshire, was originally due to finish by the end of 2019.

But a row between contractor Costain and the Welsh Government over costs could push the date back again to 2021.

Resident Mark Cottle said villagers had suffered years of noise and dust but that had "eased off" now.

"What hasn't is traffic being diverted down country lanes, articulated trucks through spaces wide enough for cars.

"Walls knocked down, trees demolished," he said.

He described "chaos on the roads" and said he was not sure the project would bring long-term benefits.

Image copyright @A465_Section2 Image caption The road is set to cost an extra £54m

The Welsh Government and contractor are at loggerheads over who is responsible for design information of the A465.

This relates to the allocation of risk - or what happens if things go wrong.

Initially, a judge ruled in favour of Costain, but this went to arbitration where it was decided responsibility should be split.

The company said the decision would wipe out half of its annual underlying operating profits - from £38m-£42m to £17m-£19m - and would mean the completion date being delayed until the first half of 2021.

Lawyer Stuart Pearson, who specialises in large infrastructure projects, said the area contained a specific type of rock that creates "difficult ground conditions".

He said it was "a very difficult balance" working out who should take responsibility.

Image caption Gilwern residents say weekend A465 closures mean drivers cut through their village, causing damage to vehicles and walls

Costain's chief executive Alex Vaughan said: "Clearly the situation regarding the A465 contract is disappointing."

The Welsh Government said the cost of the project was still £324m.

A spokesman said details of the arbitration and adjudication are "commercial in confidence" and would not be released.

"We are reviewing how the project can be concluded within the terms of the contract," he added.

"This review is nearing completion and the minister will make a further statement in due course."

Plaid Cymru's finance spokesman Rhun ap Iorwerth said there needed to be "transparency" on the issue.

"We need to have all the details, we need to know what has happened, we need to know the basis of decisions that have been made prior to and as a result of the arbitration.

"What I'm concerned about here is the use of public money and the need to make sure that public money is spent well."