A road block has been thrown up against plans to upgrade an arts centre in Powys due to the possibility that the scheme could affect the main road linking North Wales and South Wales.

Earlier this year, the trustees of Wyeside Arts Centre in Builth Wells lodged an application with Powys County Council for external alterations, an additional rear storey, extra theatre seating and subdividing the existing cinema into two smaller cinemas with additional seating.

The proposals include building a new storey which would see the creation of a “versatile” indoor assembly room that could be used for wedding receptions and even comedy or jazz club nights, and an outdoor terrace overlooking the scenic River Wye and the bridge.

But the Welsh Government has told the council not to approve the proposal – unless more information is received on how this application will affect the A470, which runs past the centre.

Kevin Price of the Welsh Government’s Department for Economy and Infrastructure said: “I advise that the Welsh Government, as highway authority for the A470 trunk road, directs that planning permission is not granted at this time as the applicant has provided insufficient information to determine the application.

“The applicant must provide the following information to support this application or resubmit the application with a Construction Traffic Management Plan (CTMP) to the local planning authority, that shall be to the approval of the Welsh Government as the overseeing organisation for the strategic road network.

“Should it become apparent that the works will impact the free flow of the trunk road, the applicant should liaise with NMWTRA’s (North and Mid Wales Trunk Road Agents) street-works team at the earliest opportunity to discuss any required traffic management measures to mitigate the impact of the work.”

Documents show that the proposal would also make changes to the inside of the building to provide modern facilities, increase accessibility and add 49 more seats for the cinema and theatre.

This would see the Castle Cinema split into two smaller screen facilities of 85 and 63 seats.

On the lower ground floor all dressing rooms will be improved with en-suite shower and toilet facilities and a new accessible dressing room is proposed at stage level with DDA (Equality Act) compliant shower and toilet facilities.

Documents explain: “The scheme has considered innovative ways to increase Wyeside Arts Centre’s (WAC) offer to this community, widening the appeal to a broader audience, so that they might become more financially resilient and sustainable in the future.

“The design aims to expand upon the existing warm and welcoming environment, reaching out to all with a quality and breadth of creative programming that will entertain, educate and excite and generate the financial and environmental sustainability that will ensure the well-being of WAC for generations to come.”

“As a result of the business planning and design work undertaken to date, WAC is now on the threshold of a major transformation which will secure its future as a dynamic 21st century arts centre providing an invaluable artistic and public resource in Builth Wells for its wider Mid Wales community.”

Next year the Wyeside will be celebrating its 150th anniversary.

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A decision on the application is expected later this month.