Supplies of Magners cider to the UK market could be disrupted if a strike at the factory that makes it goes ahead.

Unions representing some 360 staff at brand owner C&C's manufacturing plant in Clonmel, Republic of Ireland, plan to ballot for industrial action in a dispute over a 24-hour production schedule.

C&C, which also manufactures the Bulmers brand in the Republic, claims round-the-clock shifts are necessary to meet the demand for its cider. Under the proposed plan, staff would work two weeks of days, followed by two weeks of nights, with a 33% premium paid for the night shift.

The Irish Labour Court has endorsed the company's position but unions and staff have refused to accept its decision and have warned that, if a compromise is not agreed, the strike ballot will go ahead.

The Clonmel plant was expanded in recent years, and workers recruited on the strength of Magners' success in the UK. C&C is also trialling the cider in Barcelona and Munich.

However, its main target market remains the UK, where it had hoped to achieve a 40% sales increase this year. Even if a strike is avoided, it is unlikely to achieve this given the effect of the current severe weather on demand.

In addition, rival cider brands, such as the Scottish & Newcastle-owned Bulmers in the UK, have increased their penetration of the British market and are now challenging the dominant position of Magners.