The Kiwi was one of three large trawlers of special design built at Leith for the Royal New Zealand Navy at the beginning of the war, the other two being named Moa and Tui. Of 600 tons displacement, armed with one 4-inch, several smaller guns and depth-charge equipment, they were originally rated as corvettes. They were launched in 1941 and delivered on the Pacific the following year – in good time to take part with other Allied naval forces under American command in the struggle to drive the Japanese out of the Solomon Islands and adjacent territories.
On the night of January 29, 1943, the Kiwi and Moa were on patrol in the Solomons when they intercepted a large Japanese submarine, the I 1, of nearly 2,000 tons. She was armed with two 5.5-inch and some smaller guns and on paper should have been more than a match for the two New Zealand craft; but after a fierce struggle on the surface, the enemy vessel was driven aground on a shoal and destroyed. Unfortunately the Moa did not long survive this engagement. On April 7, following she foundered off Guadalcanal as the result of damage sustained in action with Japanese aircraft.
The third ship of the class, the Tui, also distinguished herself. On August 19, 1943, she sank a still larger Japanese submarine, I 17, of 2,180 tons, off New Caledonia, being aided in the hunt by American shore-based aircraft.