Building work on a series of new railway stations in and around Newport will begin in 2026, the Welsh Government has announced.

The stations will form the backbone of major public transport improvements for the city, promised as an alternative to the scrapped M4 relief road.

Relief tracks on the South Wales main line will be converted to carry passenger trains, and three new stations will be built between Cardiff Central and Newport.

Three more – including a pioneering “walkway” station for Magor and Undy – will be built between Newport and Severn Tunnel Junction.

Ken Skates, the Welsh Government’s cabinet secretary for transport, said the new stations will “allow millions of new train journeys each year” and form part of an “absolutely transformational project” for the city and surrounding areas.

The order in which the new stations will be built has not yet been decided, but the Welsh Government expects the first will be finished in 2027 and the last completed in 2030.

The Welsh Government has also announced when it plans to begin and complete other branches of the city’s transport overhaul.

These include work in 2025 and 2026 to turn Newport’s main railway station into an “interchange” for buses and trains, and the “reconfiguring” of Old Green Roundabout into a signal-controlled junction.

Work to build a “sustainable transport corridor” along the A48 between Cardiff and Newport will begin in 2025 and take five years to complete, adding dedicated bus lanes to the road and leading to “high frequency, reliable services and high passenger capacity”.

An upgrade of the nearby NCN88 cycle route will also begin in 2025, and is projected to end in 2027 – as will work to improve walking and cycling access to Severn Tunnel Junction from neighbouring villages.

Finally, new bus lanes for Malpas Road will be installed in 2027 and 2028.

The project will cost £810m, comprising a £425m contribution from the Welsh Government and £385m from the UK Government.

The new report notes the improvements around Newport “can be realised for just 1% of the cost” of HS2, in a swipe at the previous Conservative governments in Westminster, which refused to reclassify that project as England-only and hand consequential funding to Wales.

Commenting on the new report, the Welsh Conservatives’ shadow transport minister Natasha Asghar said her party would “welcome any efforts to ease congestion on our roads, [but] it is clear that Labour have no immediate plans to relieve the pressures on the M4 around the Brynglas Tunnels”.

“Labour abandoned the M4 relief road in 2019 having spent £157m on drawing up proposals, leaving motorists in South Wales gridlocked,” she added. “It is clear their suggested alternatives are moving far too slowly – despite claims of progress, real solutions like new stations and infrastructure are years away.

“The Welsh Government must axe their war on motorists and get on with delivering sensible infrastructure projects to get Wales moving.”

Then-first minister Mark Drakeford tasked Lord Terry Burns with leading a commission to identify transport improvements, following the decision to abandon the relief road motorway project on cost and environmental grounds.

The so-called Burns Commission decided public transport improvements would deliver the desired benefits for residents and commuters – and was also behind the decision to replace the variable speed cameras on the M4 in Newport with a fixed 50mph average speed limit zone.