The Unison union says it has no mandate to take further industrial action over pension plans after around half of members participating in a ballot voted to accept government proposals.
Less than 15 per cent of eligible union members took part in the ballot, with 50.4 per cent voting to reject the government's plans, and 49.5 per cent saying they were happy to accept them.
Unison head of health, Christina McAnea, blamed the disappointing turnout on 'low morale and the current difficult state of the NHS'.
'Our members in health, including nurses ... and healthcare assistants, are in the second year of a pay freeze, many face job cuts and increasing pressure at work as well as attacks on their terms and conditions,' she said.
'The low turnout coupled with the close vote shows there is no mandate to endorse the pensions' proposals, but equally no mandate to take further industrial action.'
A similar ballot by the RCN took place in February, with 62 per cent of respondents voting to reject the government's proposals. Turnout on this occasion was just over 16 per cent.
NHS members of the Unite union will take industrial action over pensions on May 10. They will be joined by public sector workers from across the union, including those working for government departments, the Jobcentre, and passport control.
Unison nad the RCN will be talking to the other health unions before deciding how to proceed.