Kyah Kennedy (16), Konnor Steele (16), Indaka Rouse (16) and O Maruhuatau Otuwhare Tawhai (17) died when their Ford Ranger ute collided with a concrete truck in a restricted speed zone in one of the city's main thoroughfares.
The crash happened at about 4pm on the rainy Friday afternoon in a 50km/h zone.
A nearby resident told RNZ it looked like nearly a head-on smash and the road had been slippery since it was resurfaced recently.
Police have not yet said who was at the wheel, what type of licence any of the teenagers had, or who owned the vehicle.
To legally carry passengers drivers must have a full licence.
The earliest this can happen is at the age of 17 and a half - and only if they have done an advanced driving course.
The police investigation into the crash continues.