By the end of 1916, the war, now well into the third year, showed little sign of reaching a conclusion and was starting to have a serious effect on morale, particularly in the French Army. The huge loss of life and atrocious conditions in the front lines were affecting the mental stability of survivors, and their initial optimism of a successful outcome was fast being eroded. The British commanders were aware of these problems and were determined to make a big effort in the coming spring to take the initiative, on the north of the line, and relieve pressure on the French in the south.
It was the view of General Haig and his staff that the enemy had suffered more casualties at the Somme than the Allies and the time was ripe to strike a major blow. Not only had the Germans suffered on the Western Front but had also sustained heavy casualties in the East with a calculated one million dead by the middle of 1916. Their hope was to foster Russia's withdrawal from the war and be able to strengthen their numbers facing the Allied forces in France and Belgium. Before this could happen the British and Dominion Forces needed to act. The third battle of Ypres was in the planning.
The severe winter of 1916/17 still held its grip into February when the New Zealander Division, which had re-organised and filled in the losses from the Somme, moved to new positions, first in the line between Sailly and St Yves then on 13 March, with snow still falling, a little further north to Wulverghem - Wytschaete, occupying the three subsections of St Yves, Wulverghem and Messines - a line they held for three months prior to the beginning of the offensive.
ANZAC II was now part of second Army under the command of General Hubert Plumer. The British had occupied this part of the Western Front since 1915 when they stopped the German advance and although being unable to dislodge them in two previous battles had spent much of that time digging tunnels under the enemy lines. These would be used and have a huge effect on the outcome of the battle.
Planning for the Third Battle of Ypres had been under way for some time and the first target would be the medieval town of Messines, situated on high ground overlooking the countryside. The task which was allocated to the New Zealanders was to capture Messines and secure the village from enemy control. The layout for the attack had the Third Australians Division on the right, the New Zealanders in the middle with a front of 1400 meters from the Douve River to just north of Wulverghem-Messines Road, and the British 25th Division protecting the left. Their objectives were the investment of Messines, and the consolidation of a line from St Yves to the Oostaverne trenches east of the town joining the Corps boundary on the left.
During this period two significant events occurred that would have a big effect on the war. On 4 April the United States declared war on Germany and Austria-Hungary and 12 days later Vladimir Ilyich Ulyanov, who called himself Lenin, arrived in Petrograd by train from Switzerland to take over control of the Russian Revolution. This move had been orchestrated by the Germans.