Porters, cleaners and other ancillary health workers are threatening strike action after talks with employers ended without agreement.
Cleaners and other NHS staff are unhappy with the pay offer
Their unions are unhappy with the government's decision to stagger a 2.5% pay rise, which they say reduces the value of the award to 1.9%.
The offer to about 300,000 non-clinical staff is the same as that made to nurses.
Unison has warned it will ballot members unless the offer is improved.
Mike Jackson of Unison said the "impasse means that we have moved a step closer to staff taking industrial action.
"This is always a last resort but with living costs soaring annually to almost 5% it is hugely unrealistic to expect our hard-working health members to survive over the next year with effectively just a 1.9% pay increase."