Zero hours 'gives me flexibility' says carer Janine Pugh
Too many councils are employing staff on contracts with no guarantee of minimum hours, the union Unison claims.
Eight of the 22 Welsh councils are currently using zero-hours contracts, research by BBC Wales has found.
Nearly 4,000 people are being directly employed on the contracts by Welsh councils, with Powys being by far the biggest user of them.
The councils say the contracts often suit the employee, and staff still get benefits like sick pay and leave.
Care Janine Pugh, whose employer in Pontypridd provides services for several councils, says the arrangement gives her flexibility.