Four dresses designed for and worn by Princess Diana are to go under the hammer at Julien's Auctions in Beverly Hills.

Three of the gowns were made by British dressmaker Catherine Walker, who was Diana's favourite designer and a close personal friend.

They're each expected to fetch between $US60,000-$80,000.

A fourth evening gown created by Zandra Rhodes is estimated to sell for US$80,000-$100,000.