A joint Australian, New Zealand, Dutch and British military intelligence unit, it saw action in New Guinea and the Solomon Islands between 1943–1945, against the Empire of Japan.

This was in contrast to its counterpart, Z Special Unit, which became well known for its direct-action commando-style raids.

A notable member of M Special Unit was Sergeant Leonard Siffleet, who was executed after being taken prisoner during Operation Whiting in 1943.

A photograph of Siffleet in his last moments achieved iconic status following the war.

[2] M Special Unit was disbanded at the end of the war on 10 November 1945.