Three people have been taken to hospital — one in critical condition — after being exposed to chemicals in Christchurch.

Emergency services were called to Coleridge Street in the suburb of Sydenham shortly before 4pm.

Firefighters had to rescue people from a commercial building.

St John said one person was in a critical condition and two others were in moderate conditions.

Fire and Emergency said seven crews attended and were remaining in the area until the site was safe, though there was no risk to the public.