SS Razmak was built at Greenock yard for P&O by Harland and Wolff, launched in 1924 and completed on 26 February 1925. She was designed for service between Bombay and Aden and spent several years in the Mediterranean Sea. When demand on her original route dried up, she was laid up. Fate then intervened by way of a disaster in the South Pacific. The Union Steam Ship Company ship Tahiti was enroute from Wellington to San Francisco on 15 August 1930, when the starboard tail shaft broke, puncturing the hull and the ship sank south of Rarotonga two days later. As a replacement the Union Company purchased Razmak, modifying it in Britain to increase the passenger capacity to 208 in First Class and 203 in Second Class. Renamed Monowai the ship sailed to Sydney, leaving that port on its first Pacific voyage on 27 November 1930. She ran a subsidized service from Wellington to Vancouver via several Pacific stops. From 24 November 1932 she ran mostly from Wellington to Sydney.
Monowai was requisitioned by the Royal New Zealand Navy on 21 October 1939 and was prepared for mounting the guns. Guns suitable for Monowai had been ordered and stored at the Devonport Naval Base in Auckland. Then followed a period of indecision, and in February 1940 work on her was suspended for over four months. After construction was completed in August 1940, she was commissioned.
The Japanese submarine I-20 conducted an unsuccessful attack on her on 16 January 1942.
Monowai was the first of two ships with this name to serve in the Royal New Zealand Navy. She was named after the New Zealand glacial lake Monowai.
As surplus, in 1943 she was transferred to Liverpool in the United Kingdom and handed over to the British Ministry of War Transport. Monowai went to Glasgow for conversion to an “Landing Ship, Infantry (Large)” or LSI(L). From June 1943 to February 1944 she was refitted with completely different armament, capacity for up to 1,800 fully equipped troops, and 20 Assault Landing Craft. She was used during the Normandy landings.
In the later period of the war she was used as a troopship transporting soldiers and after the end of the war in repatriation.
On 31 August 1946 she was returned to her owner. She resumed merchant service in January 1949 after extensive repair. In 1960 she was sold for breaking up in Hong Kong.