The Chilean Air Force has confirmed human remains have been recovered in the search for an Antarctica-bound military transport plane that crashed earlier this week with 38 people on board.

Chilean Air Force head Arturo Merino said extreme weather conditions hampered the search after the Hercules C-130 cargo plane crashed over the Drake Sea, a vast untouched ocean wilderness between South America and Antarctica.

The aircraft, which was heading to a base in Antarctica, disappeared shortly after taking off from the southern city of Punta Arenas in Chilean Patagonia late on Monday.

There were 21 passengers and 17 crew members on board.

“The condition of the remains we discovered make it practically impossible that anyone could have survived the airplane accident,” General Merino told reporters on Thursday local time.

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Extreme weather conditions, including low clouds, strong winds and massive, rolling ocean swells with an ocean depth of 3500 metres initially complicated search efforts.

The first pieces of debris from the plane were discovered by Chilean air force officials late on Wednesday.

A Brazilian ship sailing in the region also found pieces of the plane.

The Chilean Air Force located the debris from the cargo plane, found 30km south of where the plane last made contact, the Air Force said in a statement on Wednesday.

Part of the landing gear found in the Drake Sea, which separates Chile from Antarctica, among the material remains found from the Hercules C-130 cargo plane. Photo: AAP

The parts were being recovered for analysis to determine if they belonged to the cargo plane. The airforce concluded the aircraft must have crashed early the next day, given the number of hours it had been missing.

“We will continue the search and hope for a better result,” Air Force General Eduardo Mosqueira, who leads the search effort, told reporters.

Relatives of victims of the cargo plane arrive at the Legal Medical Service in Punta Arenas on Thursday. Photo: Getty

The cause of the crash was unknown.

Earlier on Wednesday, the Chilean military sent fighter jets in an expansion of its search after large rolling waves in the icy Drake Passage and low clouds had complicated the mission the day before, authorities said.

-with AAP