The union said over-crowding is unsafe for both patients and workers and is having a “devastating” knock-on effect throughout the health service.
It called on the Government to instruct the Health, Information and Quality Authority (Hiqa) to launch a probe.
Siptu health division organiser, Paul Bell, said Hiqa can conduct investigations in emergency departments under the direction of Health Minister, Simon Harris, and he urged Mr Harris to seek one into the impact of the crisis in emergency departments on the health and safety of patients and workers.
“It is the view of our members that overcrowding in emergency departments results in unsafe conditions for patients and workers, as well as having a devastating knock-on effect throughout the health service,” said Mr Bell.
"He also called on the Government to enact the Patient Safety Licensing Bill, which provides a mandatory licensing system for private and public hospitals.
“Government must also grant additional powers to Hiqa to regulate acute general hospitals and give the authority real enforcement powers. This needs to happen without delay.”