The Royal New Zealand Navy ( RNZN ) invited the United States Navy to send a vessel to participate in the RNZN 's 75th Birthday Celebrations in Auckland over the weekend of 19-21 November 2016 . The guided-missile destroyer became the first US warship to visit New Zealand in 33 years . New Zealand Prime Minister John Key granted approval for the ship 's visit under the New Zealand Nuclear Free Zone , Disarmament , and Arms Control Act 1987 , which requires that the Prime Minister has to be satisfied that any visiting ship is not nuclear armed or powered . Following the 7.8 magnitude Kaikoura earthquake on 14 November 2016 the '' Sampson '' and other naval ships from Australia , Canada , Japan and Singapore were diverted to proceed directly to Kaikoura to provide humanitarian assistance
7.8 magnitude Kaikoura earthquake
2016 Kaikoura earthquake
ANZUS