10,000 health workers will go on strike on Wednesday if further talks on Monday aren't successful.
Support-staff at various grades are involved in a row over pay and a jobs evaluation scheme with the HSE.
Talks took place between both sides at the Workplace Relations Commission over the last two days.
After some progress, it was announced that Tuesday's strike was called off.
Siptu's Paul Bell says as things stand, a 24-hour stoppage will go ahead at 38 hospitals and health facilities on Wednesday.