Three contractors have been taken to Christchurch Hospital after a wall they were working on collapsed on them in Lyttelton.
They were working on a masonry wall at the Lyttelton Working Men's Club on Wednesday. It is not known what caused the collapse.
An ambulance communications spokesperson says the men were taken to the emergency department with moderate injuries.
The Ministry of Business, Innovation and Employment has not yet said whether it will launch an investigation.