The MPAJA (Malayan People's Anti-Japanese Army) was controlled by the Malyan Communist Party (MCP). It was originally banned by the Brtish Government but became an important part of the anti-Japanese force in 1937 when Japan began attacking Malaya. It was only in 1941 that the MCP began to participate openly and legally in anti-Japanese activities after an agreement was reached between Lai Teack (leader of MCP) and Governor Shenton Thomas.

The MCP members were trained in the 101 Special Training School set up by the British Intelligence Unit under Spencer Chapman and other British officers to prepare themselves for guerilla warfare. The MPAJA operated from an intricate network in the jungle carrying out sabotage activites using guerilla warfare. The MPAJA became the most powerful resistance group in Malaya, amassing support from workers, farmers, businessmen and aboriginals like the Sakais on whom they relied on for their knowledge of the jungle.

In 1945, the MPAJA reached an agreement of cooperation with the Allied forces headquarters in India to launch a counter-offensive against the Japanese. From Feb 1945, weapons, military supplies , medicines and other necessities were air-dropped regularly in preparation for the major counter-offensive. Force 136 members airlifted into Malaya had joined the MPAJA in planning and co-ordinating the planned Malayan counter-offensive. The resistance fighters had been mobilised in groups to various parts of Malaya to sabotage the Japanese military installations during the planned Allied invasion of Malaya on September 1945.

The Allied invasion never took place as Japan surrendered unconditionally after the bombing of Hiroshima and Nagasaki.