Rescuers were notified of the avalanche in Mid Canterbury at 12.25pm.
One person was trapped in the avalanche and was in a critical condition when recovered at around 1pm, police said in a statement.
"Tragically they died a short time later.
"Nobody is unaccounted for following the avalanche, the statement said.
Rescue helicopter pilot Dan McPherson told Stuff a group was in the area heli-skiing when the avalanche happened.