South Korean authorities are to carry out an "all-out investigation" into the fatal crash involving a Jeju Air Boeing 737-800, as they release the preliminary report into the 29 December accident.

The preliminary report was released by the Aviation and Railway Accident Investigation Board on Monday in South Korea.

South Korea released on Monday a preliminary report on its investigation into a Jeju Air crash on Dec. 29 at Muan International Airport that killed 179 people in the deadliest air disaster on the country's soil.

South Korea will extend runway safety areas and redesign infrastructure after the crash of a Jeju Air Co. flight last month that killed almost everyone on board, sparking criticism that the design of the airport might have exacerbated the accident.

Authorities have suggested that migratory bird strikes were the cause of last month's deadly plane crash in South Korea, according to multiple reports.

The investigation into the deadliest air disaster on the country's soil remains ongoing, focusing on the role of bird strike and involving an analysis of the engines and the "localizer" landing guidance structure.

South Korea will remove concrete embankments from airports after the county’s deadliest domestic air disaster. The wall installed at Muan International Airport will be removed following December’s Jeju Air crash that killed almost 200 people.

The first report on last month’s Jeju Air crash in South Korea confirmed bird strikes in the plane's engines, though officials haven’t determined the cause of the accident that killed all but two of the 181 people on board.

Feathers and blood stains belonging to the Baikal teal were found on both engines of the crashed Jeju Air plane [EPA]