Talks between trade unions and the Department of Health amid industrial action have ended without agreement.
Health workers in Northern Ireland have been taking part in actions over pay and staffing levels.
Negotiators from four trade unions which represent health workers and nurses held a three hour meeting with the Department of Health in Belfast on Thursday.
Secretary of State Julian Smith, who met the unions before the meeting, had welcomed the fresh offer from the department.
But speaking on behalf of the unions, Anne Speed from Unison said it was "insufficient".
Ms Speed said: "Despite the tweet from the Secretary of State earlier this evening in the middle of discussions before the meeting concluded, our position is as follows:
The department has presented a new position, trade unions have jointly agreed this remains insufficient and falls short of our members' requirements and mandate that they have given us," she said.
"Industrial action continues and joint planned trade union action remains in place for December 18."
The delegation included Kevin McAdam from Unite and Maria Morgan from Nipsa and Pat Cullen, director of the Royal College of Nursing (RCN) in Northern Ireland.
The department said the new offer involves an additional £28 million.
Permanent Secretary Richard Pengelly described the new offer as "sizeable".
"It is a matter of great regret that unions have taken this position, indicating that industrial action will now escalate," he said.
"This will impact significantly on patient care in an already very challenging period for the health service.
"We have made a sizeable new offer. In the absence of ministers, this is the furthest I am able to go.
"It is therefore the final offer for this year."