A man has suffered acid burn injuries at a Canterbury dairy factory this afternoon.

Emergency services were called to Westland Milk Products plant at Rolleston, south of Christchurch, at 1:26pm.

Officers have been sent to the scene to help but a police spokeswoman said St John and Worksafe will be the lead agencies.

A company spokesman confirmed that a male contractor was working on the UHT filling line at the plant when he received a chemical burn.

Staff on-site responded "very quickly", he said, placing him under a water safety shower and giving him early medical assistance.

An ambulance was called and paramedics are currently treating him on-site.

Company bosses have now closed the plant, which processes milk and cream, which is largely then exported to China.

"Our priorities at the moment are obviously with the gentleman concerned and making sure he's ok," the spokesman said.

"And the second priority for us is to then immediately establish how and why this happened.

"We've got a pretty bloody good safety record at Westland and we take it very seriously. Anything like this is automatically investigated so we can see if there's any lessons to be learned."

A St John spokesman said a 55-year-old male is being taken to Christchurch Hospital's emergency department in a serious condition.