NHS staff need a raise in pay rates to protect against inflation and redress the "cut" in earnings already suffered.
In its submission to the NHS Pay Review Body, NHS Staff Side said many employees are working unpaid overtime to "fill the gaps" in service provision.
The representative body has called for a raise in NHS pay rates to a level that "protects their real value against inflation and begins to redress the cut in earnings".
Furthermore, an additional request of a pay rise for staff earning up to £21,000 has been made "in recognition of the additional pressures that inflation has placed on workers at the bottom end of the pay scale".
"The NHS workforce is committed to providing high quality patient care and contributing to improving service delivery and efficiency savings," said Christina McAnea, chair of Staff Side.
"It is time that the PRB recognised those efforts and the damage that the pay freeze is causing to staff morale.
"Not only does the Government's policy of pay restraint risk damaging morale and motivation, it also encroaches on the independence of the pay review body itself."
A recent Staff Side Survey of 34,000 members found that a third of members have very seriously considered leaving their jobs, compared to 25% in 2007.
Of those, stress and workload (75%) are given for considering leaving current employment.
Two thirds of the members surveyed said morale is "worse" than a year ago – up from 55% in 2010 - and just 8% of respondents said they would recommend their occupation as a profession in the NHS.