A 21-year-old foreign national injured after the vehicle he was driving ploughed into a truck on the icy Desert Rd remains in a critical condition.
The man is yet to learn that his three passengers were all killed in the crash about 7.15am yesterday.
Senior Sergeant Fane Troy of Taupo police says it appears their car crossed the centreline when approaching a 65km/h bend on State Highway 1 and into the path of a southbound truck.
The truck driver was shaken but uninjured.
Waikato Hospital confirmed this morning the man remains in a critical condition in its intensive care unit.
The identities of those killed, who are also foreign nationals, are expected to be revealed today.
Troy urged motorists to take care on the Desert Rd.
"The Desert Rd is notorious for changing conditions. You can have beautiful weather on one side of the hill and on the other side you can have black ice and ice and snow, so we encourage all motorists to take extreme caution."