Sydney Airport workers decontaminated after substance 'incident'

Several Sydney Airport workers have undergone decontamination after being affected by a substance on an aircraft, 9NEWS understands.

Emergency crews were called to reports up to 15 people were affected by the unknown substance at the airport about 1am today.

The incident related to an aircraft parked at an international arrival bay.

Paramedics and Hazmat crews treated and decontaminated the workers, who were then released without requiring transport to hospital, 9NEWS understands.

The exact nature of the substance remains unclear.