AG Barr has signalled plans to invest £4 million to expand its production facility and warehouse in Milton Keynes, while announcing redundancies for up to 67 staff at its carton-filling factory in Wales.

The Irn-Bru maker told investors it is proposing to introduce a high-speed carton production facility at Milton Keynes.

The investment, which includes £2m of capital costs, is designed to meet current demand for the packaging format, largely centred on its Rubicon and KA juice brands, more efficiently, while building in capacity to accommodate growth. The firm expects to create 27 roles with the move.

However Cumbernauld-based AG Barr also said it will close its in-house carton capacity at Tredegar in South Wales.

AG Barr said 67 employees may ultimately be affected by the proposals. Stating it will "do everything possible to support those affected throughout the process", it confirmed staff will be handed the chance to relocate to Milton Keynes "where possible".

Subject to employee consultation, the firm said it is proposing to close the site at the end of January 2015.

News of the Milton Keynes expansion comes just days after AG Barr told investors at its annual general meeting (AGM) in Glasgow that it was weighing up moves to further improve the efficiency of the £40m Milton Keynes plant, which came on stream last year.

Chief executive Roger White said the facility, where it handles canning for Irn-Bru and Rubicon, was "fully operational and performing as we would have hoped".

He added: "That's giving us also the opportunity to consider what else we could put in [to improve] the efficiency side in future. There is room for expansion."

In a trading update issued on Tuesday, AG Barr reported that total revenue was up 5.2 per cent for the period ended May 11, compared with the same spell last year.

It was also announced at the AGM that John Nicholson would succeed Ronnie Hanna as chairman on December 31.