“One patient, in serious condition, has been transported by road to Middlemore Hospital,” a St John spokesperson said.
Police said the Serious Crash Unit had been advised.
Earlier, SH1 was closed northbound from Hampton Downs Rd, and motorists could re-enter the expressway at Springhill Rd.
Police said the northbound lanes have now reopened.
Police thanked motorists for their patience while the scene was cleared.
Malisha Kumar is a multimedia journalist based in Hamilton. She joined the Waikato Herald in 2023 after working for Radio 1XX in Whakatāne.