Built in 1952 by Vickers Armstrong Ltd. Newcastle, for the Union Steam Ship Company (USSCo), the Māori III was intended as a replacement for Wahine I to continue the steamer express service. It was launched on 27 November 1952 by Princess Margaret. With a service speed of 21 knots, the Māori III could carry 966 passengers along with 70-80 cars. It was largely used for the overnight service between Lyttelton and Wellington.
In 1965 it went to Taikoo Dockyard & Eng. Co. Ltd., Hong Kong where it was converted to a Roll-on roll-off (RORO) design to partner with the Wahine IIto provide a drive on, drive off service. On return to Wellington in 1966 the Māori III had a new Gross Register Tonnage (GRT) of 7,498 and a large drive-on access vehicle garage.
With the arrival of Rangatira II it was laid up for sale in 1972. It was eventually bought by Wiltops (Asia) and left Wellington on 20 January 1974 under tow of the tug Mariner for Hong Kong. While enroute she was sold to Yung Tai Steel & Iron Co. Ltd. and arrived at Kaohsiung on 6 March 1974 for scrapping which commenced on 18 April 1974.