Emergency services have finished decontaminating an area affected by a strong chemical spill at Dunedin Hospital and were doing final checks on Tuesday night.

Police, fire and ambulance were called to the area after a report of a chemical spill at 4.24pm, and part of Cumberland St was blocked off for a few hours.

Southern DHB chief executive Chris Fleming said one of the lifts in a non-clinical area in the Children’s Pavilion has been closed "following the spillage of Rapicide, a high-level disinfectant and sterilant, about 3.30pm".

"The substance was disposed of in a hazardous waste area in the lower basement. This led to a release of fumes, causing this area to be isolated as well," he said.

Fire and Emergency NZ staff wore hazmat suits for protection earlier today. Photo: Craig Baxter

Mr Fleming said three staff members were checked by St John as a precaution and did not need treatment.

He said no patients, members of the public or other staff were exposed to the substance, and no part of the hospital needed to be evacuated. There was no disruption to clinical services, including the oncology block.

"Alarms were activated and people asked to avoid the affected areas, and the fire department attended to assist with the management of the substance. Alarms have since been deactivated and, as per our protocols, we have isolated the area until it can be fully cleaned."

Mr Fleming said the incident was being investigated and Worksafe would be notified.

Firefighters spray water on a person believed to have been exposed to a chemical spill. Photo: Gregor Richardson

An incident station was set up near the entrance to the oncology unit and fire crews, including two people wearing hazmat suits, worked to make the scene safe and completed checks by about 8.30pm.

The carpark in the lower basement area of the hospital had been cleared by 9pm and could now be used.

People were still able to access Dunedin Hospital from the Great King St entrance.