Chile's president and defence minister attend a press conference at an air force base in Santiago [Reuters]

A Chilean air force plane with 21 people aboard, including a popular local television host, has crashed in the ocean near the Juan Fernandez islands off the country's Pacific coast, authorities said.

The CASA 212 military plane tried twice to land at the remote islands' airport on Friday but strong wind gusts buffeted the aircraft and it later was lost from sight, said Felipe Paredes, a local council member who was in the airport's control tower at the time.

Rescuers in boats were searching for the plane, but the mayor of Juan Fernandez, Leopoldo Gonzalez, said some luggage had been found in the water.

"We assume that there was an accident and that there are no survivors," he said.

Chilean President Sebastian Pinera said authorities would do "everything necessary" to investigate the causes of the accident and recover those aboard the plane.

"This is a blow to our country. These times of anguish and uncertainty are when unity is most needed," Pinera said.

Authorities said a popular Chilean television personality was among those flying to the main island from Santiago, the Chilean capital.

Felipe Camiroaga was visiting islands to film a programme on reconstruction efforts following the magnitude-8.8 earthquake and tsunami that wiped out the main town on February 27, 2010.

The 44-year-old TV presenter was one of five people from Television Nacional's programme "Good Morning Everyone" who were travelling to the island.

"We are extremely upset," Mauro Valdes, TVN executive director, said.

Also on board was businessman Felipe Cubillos, a brother-in-law of the defence minister who had been working on post-earthquake reconstruction.

The Juan Fernandez archipelago, about 830km west of Chile's coast, is known for possibly having inspired Daniel Defoe's 18th century novel "Robinson Crusoe".

Source: Agencies