The 'vast majority' of Irish contractor Roadbridge's 215 employees have been made redundant following the firm's collapse, administrators confirmed.
Major UK highways schemes also face disruption after chairman Aidan Murphy called in the receivers.
‘My fellow directors and I greatly regret having to take this step, but unfortunately, it was the only possible option at this time,’ said Mr Murphy.
‘The Board recognise the support of all our stakeholders, including our bank, Bank of Ireland, in difficult circumstances as the directors explored every opportunity to save the company.
‘We are committed to working closely with the receivers now in order to get the best possible outcome for employees, creditors and stakeholders.’
Roadbridge is part of the Future Valleys consortium, along with Tarmac subsidiary Alun Griffiths and Spanish construction giant FCC, which is building the £513.6m final two sections (Dowlais Top to Hirwaun) of the A465 Heads of the Valleys scheme for the Welsh Government.
Construction began in January and is due for completion in the summer of 2025.
Roadbridge was due to start work in May on a £25m package of works to dual a section of the A470 at Hirwaun but a Welsh Government spokesperson told Highways: ‘We do not expect Roadbridge’s financial difficulties to affect progress on the A465 between Hirwaun and Dowlais; however we continue to monitor the situation closely.’
This summer, a joint venture between Roadbridge and John Sisk was due to start work on section two of the A5 Western Corridor in Northern Ireland.
The full scheme comprises an 86-km stretch of dual carriageway between the urban centres of Londonderry, Strabane, Omagh and Aughnacloy for the Department for Regional Development’s roads service (DRD Roads).
A spokesperson for DRD Roads said: ‘We are aware of this matter and will be considering the implications for A5 delivery in due course.’
Sisk would not comment on whether it would seek a new partner, but said: ‘We remain committed to the A5 project and will be engaging with the client’s representatives to satisfy the appropriate procurement requirements and to demonstrate our capacity to continue with the project.’
Roadbridge was also working on two packages on the HS2 rail link and was also working on major roads schemes in the Republic of Ireland.
Work was due to start this summer on a £168m upgrade of the N5 road between Ballaghaderreen and Scramogue in Roscommon in the Republic of Ireland, which was awarded to Roadbridge last year. The failed company also won the £29m Coonagh to Knockalisheen distributor road scheme.