The family of a Gold Coast sailor, missing off the coast of Chile since a massive earthquake triggered a tsunami two weeks ago, fear for his safety.

Mitchell Westlake's family last heard from him on January 16 when he left Salinas, Ecuador, to go on a sailing course.

The yacht was expected to dock at the Chilean city of Coquimbo between February 24 and 27, the day the earthquake struck.

Chilean authorities are understood to have launched a search for the boat on which the 23-year-old Merrimac man and four others were sailing, the 13-metre yacht SS Columbia.