Tesco stores nationwide could face strikes in the new year, a union has warned.

Stores in Sligo and Carrick-on-Shannon, Co Leitrim, are set for major disruption during the Christmas period,

The Mandate trade union has said strike action will take place on December 6, 14 and 22. However, Tesco has insisted it will remain open on these dates.

Tesco has called on Mandate to call off the strike action and said “they are in breach of the company and unions agreed procedures which are to refer disputes to the Workplace Relations Commission (WRC)”.

Mandate general secretary John Douglas told the Irish Independent that strikes in other stores are unlikely before Christmas. However, he said there could be major disruption come 2019.

Mr Douglas said problems with canteen facilities are among a number of local issues that need to be addressed.

“There are 147 stores nationwide and the attitude of the company is the same across those stores… The likelihood is that this is going to become more prevalent,” he said.

However, Tesco defended its treatment of employees and said the union was inconveniencing customers.

“If Mandate proceeds with the proposed unwarranted one-day strike actions for the two stores, both will continue to remain open to serve customers,” a statement read.

“A conciliation conference on the two issues in Sligo was scheduled at the WRC for October 24 but was rejected by Mandate. In Carrick-on-Shannon, the matters have not yet been referred back to the WRC by Mandate. Tesco has always abided by agreed procedures and we expect Mandate to do the same,” it added.