In a ballot, 68% voted for strike action and 88% indicated they would be willing to take industrial action short of striking. As of yet no date has been set for the proposed action.
The ballot was called over health secretary Jeremy Hunt's decision to ignore the recommendations of the NHS Pay Review Body earlier this year.
The body advised the government to offer all staff a blanket pay rise of 1%. Instead, Hunt opted to offer workers incremental pay increases, which meant only those at the top end of the pay increments are guaranteed any kind of pay award.
Unison general-secretary David Prentis called the strike an example of "anger turning into action".
"Refusing to pay them even a paltry 1% shows what the government really thinks about its health workers. Inflation has continued to rise since 2011 and the value of NHS pay has fallen by around 12%," he said.
"We know health workers don’t take strike action lightly or often. The last action over pay was 32 years ago. But we also know a demoralised and demotivated workforce isn’t good for patients."
He stressed that any action would include steps to "minimise the impact to patients".
NHS Employers director of employment and reward Gill Bellord said she "remains hopeful" an agreement can be reached before the proposed strikes take place.
"Employers need to maximise their ability to retain staff and plan changes to how they work in response to the changing needs of patients and major financial challenges have made stark choices inevitable," Bellord said.
“We need to remember that staff and patients have benefited hugely from the positive industrial relations climate that has existed in the NHS for a generation. I know that NHS organisations and trade unions - and indeed our patients - will not want that to be lost.”
