More than 170 trampers were airlifted across flood-prone parts of the Milford Track yesterday after heavy rain caused rivers to rise.

The Conservation Department's Fiordland tracks ranger Ken Bradley said rain fell at 30mm an hour from 6am until 10am, with rivers rising 3.8m stranding trampers.

Three helicopters were called in to airlift guided and freedom trampers over the most flood-prone sections of the track.