During the First World War, the regiment was first sent to capture German Samoa in August 1914 and was later affiliated with the New Zealand Rifle Brigade which saw combat on the Western Front.

In 1867, the Wellington Veteran Volunteer Corps was formed from former soldiers of British regiments which had served in New Zealand.

Many of the men were disgusted by the mismanagement of the expedition and the volunteers returned to Wellington in October once their three months of service had been completed.

The battalion structure returned once again in 1895 and this time the City Rifles and Guards became part of the Wellington Battalion of Infantry Volunteers, which constituted all of the infantry volunteers of the Wellington Military district (the lower half of the North Island).

[7] During the Second Boer War (1899-1902), the New Zealand Government sent a number of mounted rifles contingents to fight in South Africa.

[11] With the out break of the First World War in August 1914, the British Government requested for New Zealand to send a military force to capture the German colony of Samoa.

[12] The 5th (Wellington) Regiment provided two infantry companies, for a total of 559 men, which was the largest contribution of any unit in the New Zealand Military Forces.

[13] After the Samoa expeditionary force had been despatched, the New Zealand Government decided to form an infantry brigade of four battalions from the existing territorial regiments.

It initially consisted of two battalions, which arrived in Egypt in November 1915 and became part of the Western Frontier Force.

[19] The Wellington Regiment remained in New Zealand for home defence during the Second World War and raised a 2nd battalion in November 1940.

[25][26][27] These battalions formed part of the 2nd New Zealand Division and saw action in Greece, Crete, North Africa, Tunisia and Italy.

[24] The Wellington Regiment also supplied men to the 36th Battalion of the 3rd New Zealand Division, which saw combat at the Treasury Islands.

[29] During the Royal visit of New Zealand in 1953/54, the Wellington Regiment was granted the unique privilege of mounting the full Military Guard of Honour at the 1954 State Opening of Parliament.

The Wellington Rifle Battalion received a stand of colours in 1887 and were used until 1929 when they were finally laid up in St Paul's Pro-Cathedral.