A police spokesperson said the three-vehicle crash was reported to police about 8.30am on Wednesday.
The crash, which occurred in the northbound lane of Main South Rd (SH1) near Weedons Rd, caused major delays for motorists.
The spokesperson said one person sustained moderate injuries and another minor injuries in the crash.
"Diversions are in place, however, the crash is causing delays."
The northbound lane, north of the Weedons Rd interchange, was blocked.
"Motorists are advised to expect significant delays and to avoid the area," a Waka Kotahi NZTA spokesperson said.
There was also debris on the road from an unsecured load near the crash scene.
"Additional debris from an unsecured load north of the crash, across both northbound lanes as well as a southbound lane will require traffic management to clear," the Waka Kotahi spokesperson said.
