South Korea ordered Monday a "comprehensive inspection" of all Boeing 737-800 aircraft operated by the country's carriers, after a Jeju Air plane crash-landed and burst into flames, killing 179 people on board.

US air safety officials and staff from the beleaguered aircraft maker Boeing were arriving to join investigators probing the worst air disaster on South Korean soil, which officials initially blamed on a collision with birds.

The plane was carrying 181 people from Thailand to South Korea when it made a mayday call and belly-landing before crashing into a barrier and bursting into flames.

Everyone aboard Jeju Air Flight 2216 was killed, save two flight attendants pulled from the wreckage.

South Korea began seven days of mourning, with flags flying at half-mast and the acting president flying to the crash site in southwestern Muan for a memorial.

Acting President Choi Sang-mok, who has only been in office since Friday, said the government was making "every effort" to identify victims and support bereaved families.

Choi, an unelected bureaucrat who became acting president after his two predecessors were impeached, said a "thorough investigation into the cause of the accident" would be conducted.

He also said South Korea would conduct "an urgent safety inspection of the overall aircraft operation system" to prevent future aviation disasters.

South Korea has a solid air safety record and both black boxes from Flight 2216 — the flight data recorder and the cockpit voice recorder — have been found.

Officials have so far identified 146 victims using DNA analysis or fingerprint collection, said deputy minister for civil aviation, Joo Jong-wan.

"As for the comprehensive inspection, maintenance records of key systems such as engines and landing gear will be thoroughly reviewed for 101 aircraft operated by six airlines using the same model as the accident aircraft," he said. 

"This process will be carried out intensively starting today and continuing until 3 January, 2025."