A major regional health service in Queensland is facing charges over alleged failure to protect its staff.

The state’s Office of the Work Health and Safety Prosecutor has charged Darling Downs Hospital and Health Service (DDHHS) with four counts of failing to ensure the health and safety of workers.

The charges follow incidents in which a patient who had been transferred from prison to Toowoomba Hospital's Acute Mental Health Unit attacked a nurse, striking them in the head and attempting to choke them.

In a separate incident, a nurse at a residential aged care facility had a knife held to their throat. 

DDHHS is accused of failing to implement safety measures, such as conducting health safety risk assessments before admitting patients and ensuring multiple staff are present in dangerous circumstances, and failing to provide adequate training.

If found guilty, the health service faces fines of up to $1.5 million for each of four offences.

The case is scheduled for the Toowoomba Magistrates Court in May.