WELLINGTON, New Zealand (AP) — One Australian and two German climbers were missing Wednesday on New Zealand's tallest mountain after failing to return from a summit attempt two days earlier.

A brief aerial search was called off due to bad weather and is unlikely to resume before Thursday.

Police said the men were last seen at 4 a.m. Monday by a returning guide as they attempted to reach the top of Mount Cook, which is also known by its indigenous Maori name, Aoraki. Police said the men were roped together when they set off from a hut for their climb at about 1:30 a.m.

They were due back at a hut Monday night.

Senior Constable Brent Swanson said he believes Johann Viellehner, 58, from Germany, and his son Raphael Viellehner, 27, had teamed up for the climb with Michael Bishop, 53, a Sydney doctor.

He said the weather on Monday was clear and well-suited for climbing but there are plenty of hazards on the mountain, including avalanches, rock falls and crevasses. He said the men seemed to be well-equipped although didn't appear to be carrying emergency locator beacons. He said cellphone reception is poor on much of the mountain.

"At the moment, we're still hopeful they're OK," Swanson said. "There are things they can do, like build a snow cave or find shelter in certain areas. We just don't know the circumstances of what happened."

The mountain is 3,724 meters (12,218 feet) high.