Usdaw, the union for shop workers, has called for new legislation guaranteeing minimum hours for staff when a trade union demands such a contract to tackle exploitative zero-hours contracts.
Delegates were responding to the recent revelation that 1.4 million workers are employed on a zero-hours contract.
Usdaw deputy general secretary Paddy Lillis criticised employers for defending the practice as “necessary for the business.”
He said: “This is not the case. The widespread abuse of zero hours must stop.
“Zero-hours contracts are not being used by small companies who don’t know if there will be work next week. It is being done by big companies to exploit workers.”
He added: "95 per cent of Usdaw members have a minimum hours’ contract. However the job is not finished. Usdaw officials will continue to make sure zero-hours contracts stay out of workplaces where we are recognised.”
Pat Harrington, general secretary of the Solidarity union commented:
"Labour leader Ed Miliband’s commitment to make employers offer minimum hours contract after six months on zero hours is not enough. To start with we would like legislation to ensure that a minimum hours contract is offered after 12 weeks."