The award, to be made in two instalments, was described by Unison's head of health, Karen Jennings, as a "paltry pay offer".
"If the government refuses to negotiate, or refuses to make an improved award then we will ballot our members and recommend a vote for industrial action up to and including strike action," she said.
"It's time the government to stop trying to defend the indefensible and to start listening to the largest workforce in Europe - the NHS."
The Department of Health (DoH) has said the pay increase is "sensible" and "fair for staff" but Ms Jennings dismisses this view as "living in cloud cuckoo land".
"With inflation running at 4.8 per cent this is a pay cut which is certainly not fair and it would not make sense to accept it," she added.
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