The union said around 100 of its members will strike between 14 and 19 April over GH London’s "failure to pay wages on time" and "failure to introduced promised improvements to sick pay". Members voted by 96% for industrial action.
Unite general secretary Sharon Graham said workers need "every penny of their wages" paid on time amid the cost-of-living crisis in the UK.
"GH London has to get a grip to sort out its payroll and stick to its promise to give company sick pay to all employees," she added.
"Unite is entirely dedicated to defending our members’ jobs, pay and conditions and GH London’s workforce have the union’s full backing during these strikes."