Upon receiving word on 6 August 1914 that war had begun, a feldpost service was quickly organized to serve the postal needs of local German military and police forces. The service was limited to postcards weighing no more than 50 grams, and had no postal facilities of its own. Approximately 1,000 postcards were handstamped with a rubber stamp “Feld-[Postkarte]”, “Absender Dienstgrad” (sender’s rank), and the instructions “nur für die Wehrabteilung und für die Expeditionstruppe” (only for the Defense Corps and the Expeditionary Force). These postcards were then authenticated by the addition of a rubber stamp of the official seal of the Rabaul post office.

Most of these feldpost cards were sent to the post offices in Rabaul and Herbertshöhe for distribution to the forces, with a few sent to Bitapaka and Toma. On 12 August 1914, Australian forces destroyed portions of the post offices in Rabaul and Herbertshöhe, but did not occupy the towns. The post offices remained open until mid-September 1914, but no additional feldpost cards could be created during the intervening weeks, as the Rabaul official seal had been destroyed. Any feldpost cards after approximately 12 September 1914 were created simply by handwriting “feldpost” on a postcard. However, the normal cancellers were not destroyed on 12 August 1914, and the then-existing feldpost cards could still be used until the closing of the last German post offices in mid-September 1914.