At the outbreak of war in 1939 it was decided that New Zealand should provide an Expeditionary Force of one division. This force became known as 2nd New Zealand Expeditionary Force and the division as 2nd New Zealand Division. The first echelon of 2 NZEF Headquarters and a Brigade Group landed in Egypt in February 1940. The second echelon, also a Brigade Group, was diverted to Britain on Italy's entry into the War and did not reach Egypt until March 1941. The third echelon arrived in Egypt in September 1940 and concentration of the division was completed just before it was deployed to northern Greece in March 1941. In the meantime transport and signal units had taken part in the First Libyan campaign and the destruction of the Italian Army in Libya and Cyrenaica.
When powerful German forces invaded Greece in early April, the Greek Army collapsed and the British Expeditionary Force was obliged to retreat to embarkation beaches in the south. The New Zealand Division fought a series of sharp and successful rearguard actions before embarking by brigades in good order in the last days of April. Two brigades and some divisional units were evacuated to Crete, where the Germans began their airborne attack on 20 May. After six days of very heavy fighting the defenders retreated, most being evacuated to Egypt. Many remained, however, and were taken prisoner.
The reorganised and reinforced division was next engaged in Operation Crusader in Libya in November/December 1941, taking part in very severe actions there and suffering heavy casualties.
After spending a few months in Syria the division returned to Egypt in June 1942 after the fall of Tobruk, and was continuously in the field until the North African campaign ended with the surrender of the Axis forces in Tunisia in May 1943. It was engaged in the battles of Matruh, on the Alamein line, Alam Halfa, El Alamein, the Mareth line and Enfidaville.
Moving to Italy in October 1943, the New Zealanders were engaged there almost continuously until the end of the war. They took part in the battles of Sangro River and Cassino, the advance to Florence, the battles for the Gothic line and the series of battles which ended in the capture of Trieste in May 1945.
Before Japan entered the war New Zealand had mobilised her Territorial Army, commenced the formation of a Home Guard and had provided garrisons for Fiji and Fanning Island and later for Tonga and Norfolk Island. The Fiji force (which became 3rd Division) was relieved by American troops in July 1942 and moved to New Caledonia at the end of the year. The 3rd Division carried out three important island operations to capture Vella Lavella, Treasury Island and the Green Islands.
The 28th (Maori) Battalion served with great distinction throughout the Middle East campaigns and in North Africa and the Mediterranean.
The New Zealand Division of the Royal Navy was soon active in the Second World War. The cruiser HMS Achilles fought bravely in the Battle of the River Plate in December 1939, losing four of her crew. Her sister ship HMS Leander undertook escort duties in New Zealand waters and in the Red Sea, hunted German raiders in the Indian Ocean and helped in the invasion of Syria.
In September 1941 the division was redesignated the Royal New Zealand Navy. Following Japan's entry into the war both Achilles and Leander protected convoys between the USA and the South Pacific. In 1942 Achilles was involved in operations at Guadalcanal, and in July of the following year Leander was badly damaged by a Japanese torpedo in the Solomon Islands.
HMNZS Gambia, transferred from the Royal Navy, took part in actions against the Japanese off Ceylon and at Okinawa, and Achilles rejoined the Fleet for the final operations against the Japanese.
New Zealand minesweepers saw continuous service in tropical waters from December 1941 to mid 1945. Their most notable action was the sinking of the much more heavily armed Japanese submarine I-1 by the Moa and Kiwi after fierce action off Guadalcanal in January 1943.
About 7,000 New Zealanders served in the Royal Navy during this war, seeing active service from Spitzbergen to Cape Horn and from Iceland to Japan, taking part in every major naval operation as well as the routine daily tasks of the Royal Navy.
At the outbreak of war the Royal New Zealand Air Force had a total strength of 1,160 all ranks and was poorly equipped. A large expansion programme was planned and carried through. At the peak, in June 1944, the RNZAF had a strength of nearly 42,000.
Five hundred New Zealanders were serving in the RAF in September 1939. During the course of the war a further 11,000 would be attached to the RAF. They were represented in almost every important operation of the Air War, serving in all commands and theatres.
RNZAF squadrons served in the Pacific War almost from the beginning. Strength was built up to a maximum of 15 fighter, bomber and transport squadrons. They were actively engaged throughout the South-West Pacific campaigns.
Related: see Second World War information on NZHistory.net.nz