I have passengers on two sailings of the immigrant ship "Rangitiki" from London to Auckland via Panama Canal.
The voyages were: arrive Auckland 1 November 1958, and arrive Auckland 18 Mar 1959 and the passenger lists are on familysearch.
I found a list of departure dates here: https://natlib.govt.nz/records/38036085 , which says left London 13 Feb 1959 which I assume matches the arrival 18 Mar 1959 (but omits the sailing which arrived 1 Nov 1858).
Ship category: https://www.wikitree.com/wiki/Category:Rangitiki_%272%27_%281929%29