An historic back-country hut in the Arthur's Pass National Park has burnt down.

Photo: Supplied / DoC

A tramping group in the area came across the smouldering remains of Casey Hut on Saturday afternoon.

Fire investigators assessed the site today, and believe the fire started around the hut entrance or by the wood-stove.

Photo: Supplied / DoC

Department of Conservation ranger Pete Brady said the hut was built in the 1960s and was one of the first commissioned by the Arthur's Pass National Park Board.

He said it was a big loss as the hut was in a popular area for weekend tramps, and was a starting point for longer walking routes.