It concerned the jurisdiction over and administration of civil affairs in Dutch East Indies territory liberated by an Allied expeditionary force during WWII.
[2] The first agreement for postwar policy planning in regard to Japan and areas under Japanese control, between the United States and the Netherlands, were signed in London, on May 16, 1944.
It was agreed that the Allied forces in the liberated areas would be utilized for NICA's administrative tasks, but due to political conflicts with the American State Department - which wanted the Netherlands to commit to a date for the colony's independence or full autonomy according to the Atlantic Charter, signed by the Dutch government - it took until 10 December 1944 for the parties (Hubertus van Mook and Douglas MacArthur) to sign the Van Mook–MacArthur Civil Affairs Agreement.
Its key provision was that areas recaptured by Allied troops would revert to Dutch rule via the Netherlands Indies Civil Administration (NICA).
By the time Japan surrendered, NICA units and 1st Infantry Battalion (KNIL) had landed in New Guinea (Hollandia, Biak, Numfur and Manokwari), the Moluccas (Morotai) and Borneo (Tarakan and Balikpapan).