Three university students have been rescued after becoming lost in heavy fog in the hills above Dunedin last night.

A fourth member of the group raised the alarm about 9pm after walking out of the area, Dunedin police search and rescue coordinator Sergeant Richard Panting said.

More than 30 police staff and volunteers were involved in the search to locate the remaining, who were lost on Mount Holmes.

The group had gone to the Mount Cargill walking track for a run in the late afternoon.

"When they went out it was pretty reasonable," Sergeant Panting said.

However, conditions deteriorated during the evening and the group became disoriented.

"It's pretty easy to see how they got waylaid,'' he said.

"Visibility was down to 10m due to the fog. It was pretty nasty up there.''

The group was found at 10.30pm more than 200m off the track. They were cold, but otherwise uninjured.

Sergeant Panting praised their actions.

"When they got lost they did the right thing. They stopped moving, which made it easier for us [to find them].''