A police spokesperson said emergency services responded to the two-vehicle crash at the intersection of Edgeware Rd and Cranford St, St Albans, at 8.07am on Thursday.
"Initial indications suggest there are injuries," police said.
St John spokesman Gerard Campbell said two people received moderate injuries in the crash and four others had minor injuries.
He said all six patients were transported to Christchurch Hospital.
A Transport for Christchurch spokesperson said the intersection is now open and the crash has been cleared.
Cranford St was reduced to a one lane at the intersection after the crash.