Big supermarkets spend an average of 29.5 hours each week drawing up staff schedules, with some spending up to 80 hours on the task.

A survey by software provider Kronos found that grocers worked on rotas

for longer than retailers in other sectors.

Most supermarket managers said their stores didn't have enough staff. Some 98% said stores were often understaffed for the volume of work and all agreed service would be enhanced if staff scheduling was improved.

Budget constraints, holidays, sickness, staff turnover and unpredictable customer flow were highlighted as barriers to getting staffing levels right.