Pukaki and Hawea escorted the Antarctic supply ship Endeavour from Bluff to the edge of the pack ice on the Endeavours first voyage south in late Dec 1956. To relieve the USN weather picket ships on their station at 60 South 170 east 900 miles South of Bluff, the RNZN fitted Rotoiti out as a weather picket ship in 1961. On 2 Oct 1961 she sailed from Auckland on the first patrol, to provide weather information and be on emergency standby for the US aircraft flying between Christchurch and McMurdo. Based at Dunedin, each patrol was on station for 10 - 12 days, with usually two patrols in October - November, and one or two in January - February, the season ending early in March. Weather and sea conditions were usually bad to severe, with icebergs, snowstorms and icing up among the natural hazards. Rotoiti did three tours in the 1961-62 season, two in late 1962, and her last two ending 3 Dec 1963. Pukaki was similarly modified and took over in mid Jan 1964 for two tours. 1964-65 was the last season, Pukaki doing five tours including one over Christmas. Her last patrol ended on arrival at Dunedin 23 Feb 1965. Both ships were withdrawn from service within months on account of poor hull condition.