Thousands of local government and school support workers across Herts will strike in a row over pay next month.
The industrial action has been called by Unison, which has around 8,500 members in the county, for July 10.
The dispute stems from workers’ three-year pay freeze, followed by a 1% pay rise.
The union’s regional secretary for local government Ann Glover said: “Many of our members are low-paid women earning barely above the minimum wage, who care for our children, our elderly and our vulnerable and they deserve better treatment than they have had at the hands of this government.
“The employers must get back into talks immediately to avoid a damaging dispute.”
Derrick Ashley, Herts County Council cabinet member for resources, said: “The proposed industrial action is based on national issues over pay, although Hertfordshire County Council is continuing to hold conversations with the unions locally to try and help find a resolution.
“In the meantime, we will be planning ahead to minimise the impact of any strike on council services, particularly those for vulnerable people, to ensure that it will be ‘business as usual’ as much as possible on the day.”