Fire and Emergency NZ is working to identify the hazardous substance that forced businesses to be evacuated in Christchurch on Monday afternoon.

Fire crews from the Christchurch City, Spreydon, Woolston, and Wigram stations were called to the incident on Buchan St in Sydenham just before 1pm.

One person was taken to hospital, businesses were evacuated and workers in the area were told to remain indoors during the incident.

Firefighters were seen wearing breathing apparatus at the scene.

Hato Hone St John said it treated two people at the scene, one of whom was taken to Christchurch Hospital by ambulance in a moderate condition.

A cordon was temporarily put in place and fire crews left the scene at 3.30pm.

Fire and Emergency NZ said it was working to identify the substance.

-With RNZ