Image copyright HolderMatthias/Rightacres Image caption An artist's impression of the new Cardiff bus station includes some of the planned apartments, shops and offices

Work can finally start on Cardiff's long-awaited new bus station - but it will not open until 2023.

It had originally been planned to open in 2017, but after setbacks, a new master plan was approved last November.

The Liberal Democrats - who ran Cardiff council when plans were first drawn up - accused the Labour-led administration of "staggering incompetence".

But the ruling Cardiff Labour Group said building the bus station had been "a number one priority".

A deal has now been struck with financial backers which paves the way for construction to begin.

But Councillor Rodney Berman called the timeline to opening "unbelievable", adding: "Plans were initially being drawn up for a new bus station by the council administration which I and the Liberal Democrats led between 2004 and 2012.

"We left office in 2012 with a funded plan in place - all that was required then was to acquire the site of the former NCP car park in Wood Street.

Image copyright HolderMatthias/Rightacres Image caption The bus interchange will be the final stage of the Central Square redevelopment in the city centre

"We knew that might take some time, but nothing like the time we've had to wait since."

He said "deadline after deadline has been missed", adding that since the old station was demolished in 2015, bus services have been "scattered to the wind around the city centre".

The ruling Cardiff Labour Group described the claims as "untrue".

It added: "All that was in place when he left office, was a hastily put together artist's impression."

Council leader, Huw Thomas, said building the bus station had been "a number one priority".

On Tuesday, developer Rightacres confirmed a large sewer will be moved in the coming weeks to allow construction work to begin in late November.

This should be completed by mid-2022, when the station is due to be handed to Transport for Wales.

The Welsh Government said at this point, the station will be a "shell", and Transport for Wales will begin fitting it out.

This work will take between six and nine months, meaning the first passengers will not be able to use it until the spring of 2023.

Image copyright Nancy Cavill Image caption AMs Jenny Rathbone and Julie Morgan said the bus station was a crucial part of the city centre

The interchange will have bays for 14 buses on the north side of Cardiff Central railway station, with more planned for the south in the future.

It will also include apartments, shops and offices.

Cardiff Central AM Jenny Rathbone said the deal was a "major milestone" as the city urgently needed an integrated, modern public transport system.

Paul McCarthy, chief executive of Rightacres, the firm leading the development, said: "Unlocking this development has been a complex process."

It will be built on land next to the new headquarters for BBC Cymru Wales in Central Square, on the site of the former bus station.

Council leader Mr Thomas said: "This will be the final stage of the completion of Central Square, which is the biggest regeneration project in Wales.

"The council's original masterplan for this part of the city is now a reality and we are delighted that through it, thousands of jobs are being created in the Welsh capital."

Transport Minister Ken Skates said the bus interchange was a key component in a metro transport hub.