Members of the Unite union who work in the health service in Northern Ireland and Britain are staging a day of industrial action over pay.
The work-to-rule protest will include a ban on non-essential paperwork, email exchanges, attendance and meetings and telephone calls.
Health service staff are protesting over what they say is a derisory three-year pay deal imposed by the British government.
The union said the deal would work out at a 2.5% increase per year.
Demonstrations will be held outside hospitals where staff will hold a work-to-rule protest.
However, emergency cover will be maintained.
Unite's Senior Regional Industrial Organiser Albert Mills said their members were 'furious' at the deal.
'Unite members in Northern Ireland have voted for strike action. But they feel they need to put a warning shot across the bows of Health Minister's Michael McGimpsey department. We are willing to talk, but he seems unable or unwilling to do so,' he said.
