Supermarkets are facing a summer of discontent over industrial disputes at depots, with union relations increasingly tense.
Morrisons is braced for up to 600 employment tribunals in relation to disputes at its now closed Aylesford depot. And Asda is scheduled to receive ballot dates for depot strike action this week.
The Morrisons cases relate to allegations by the GMB regarding millions of pounds of unpaid redundancy money and bank holiday wages.
A spokesman for the chain said that not all cases would go to tribunal. "Only where fundamental differences cannot be resolved will they be considered by an employment tribunal."
Meanwhile, it was reported that Iceland was to review its distribution network. The GMB said Iceland was looking to move its depot from Deeside to a former Safeway Warrington site. The GMB indicated that Deeside could retain the distribution for the Iceland-owned Cooltrader chain.