NHS workers will today deliver a giant envelope to the Health Department to mark the start of a ballot for strikes in a bitter row over pay.
Members of Unison will stage the protest at the department's head office in London, as ballot papers are sent to 350,000 union members in England.
Unite and the GMB are balloting their health members across England, Wales and Northern Ireland after the coalition controversially decided not to accept a recommended 1% pay rise.
The ballot results are due at the end of September, threatening industrial action in October.
Council workers are due to strike on October 14 in a separate row over pay, while the TUC is staging a national demonstration on October 18 to highlight the impact of the Government's spending cuts.
Unions estimate that the 1.3 million workers in the NHS have seen their pay fall by up to 15% in real terms since the coalition came to power in May 2010.
The Unison members, including nurses, paramedics, therapists, cooks, cleaners, healthcare assistants and admin staff, are being asked to vote in favour of industrial action.
The union said the Government's decision not to accept the review body's recommendation would mean that 60% of NHS staff, including 70% of nurses, will not receive a pay rise this year.
A Department of Health spokesman said: " Since May 2010, there are 13,500 more clinical staff caring for patients and we want to protect these increases. We cannot afford a general pay rise on top of incremental pay increases without risking frontline jobs.
"We are disappointed that unions are balloting for industrial action. There is still time for the unions to put patients first and accept our offer to come back to the negotiating table."