Representatives from Usdaw called for urgent reform yesterday, during a Commons' Scottish Select Committee hearing in Falkirk.
Karen Whitefield, who is the campaigns officer at Usdaw, said: "If major supermarkets can respond to business fluctuations without resorting to zero-hours contracts then why can't many of the businesses that currently use these contracts?
"Whilst most Usdaw-organised workplaces don't have zero-hours contracts, one in every four Usdaw members knows someone - a friend or family member - who is employed on a zero-hours contract."
Ms Whitefield suggested that such contracts are widespread, especially in workplaces that don't have a trade union.
Critics argue businesses that use zero-hour contracts save money by not paying any sickness and holiday entitlements as well as overtime.
Sports Direct, McDonald's, Cineworld and Amazon are among those companies that use the contracts.