Tokyo is sending almost 1200 troops to join relief efforts in the typhoon-ravaged Philippines along with three warships, 10 planes and six helicopters.
The aid deployment will be the single largest by Japan’s military.
About 1170 members of the nation’s Self-Defence Forces (SDF) will provide medical support and quarantine services, and transport relief goods, the ministry said in a statement posted on Friday.
Ten or so others will be based in Manila to coordinate relief operations with the Philippines and other countries.
The aircraft include seven C-130H transport planes, two KC-767 tanker planes and one U-4 multi-purpose support plane.
Japan initially dispatched 50 SDF members on Tuesday to assist in medical support and transport operations and said on Wednesday it was readying as many as 1000 troops to go to the Philippines.
It is the first time Japanese troops have been active in Leyte since the island turned into one of the biggest battlegrounds of World War II, when US forces counter-invaded in 1944.
Many of the reinforcements were scheduled to leave Japan on Monday and arrive in the Philippines around Friday.
The 1180-strong contingent will be the largest single relief operation team ever sent abroad by Japan’s defence forces.
The previous record number was 925 sent in January 2005 to Sumatra after the Indonesian island was ravaged by a massive earthquake-triggered tsunami.
Previous overseas missions by the SDF, which adheres to the country’s post-war pacifist constitution, have usually numbered in the hundreds.
They included UN peace-keeping missions in Cambodia and East Timor as well as logistical activities in Iraq and naval refuelling operations in the Indian Ocean to back the US military in Afghanistan.
In June this year, about 1000 members from Japan’s land, sea and air defence forces took part in joint amphibious landing exercises with US forces in the US state of California.
The drills were widely seen as aimed at coping with China’s naval expansion while Tokyo was locked in a simmering row over a group of Japan-controlled Senkaku islands which Beijing also claims and calls the Diaoyus.