Local government workers are to be urged to reject a 1% pay offer and asked if they will support industrial action.
The GMB union said council staff have had an 18% real terms pay cut and suffered 440,000 job losses in recent years.
National officer Brian Strutton said: "A national meeting of senior lay representatives unanimously agreed to consult our 220,000 on the offer.
"The meeting agreed to recommend that members reject this offer and that they be asked if they will support industrial action. Council staff have had only a 1% pay rise in the last five years and it is a terrible indictment that the national minimum wage has caught up with them.
"It's scandalous to think that people who work for councils could not legally be paid any less, yet day in and day out they serve their communities in schools and academies, care homes, emptying bins and cleaning streets, protecting vulnerable children and all the other jobs they do."
Protests were held to highlight the "dire" state of council workers' pay after years of having increases held down by the Government.
Unison organised events across the UK today on the 15th anniversary of the introduction of the national minimum wage.
Heather Wakefield, Unison's head of local government, said: "Local government workers and the services they provide have faced four years of devastating cuts under this Tory-led Government and today our members are saying enough is enough.
"The national minimum wage was introduced to protect workers who are most vulnerable to low pay. It was not designed as a tool to benchmark the pay of skilled workers delivering essential public services."