The passenger list can be browsed for other "Hansens" here:
"New Zealand, Archives New Zealand, Passenger Lists, 1839-1973," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:S3HY-6SRV-M2?cc=1609792&wc=MP7R-MJ6%3A119046201%2C119035002%2C119520701 : 21 May 2014), Canterbury > 1872 > Palmerston > image 1 of 10; Archives New Zealand, Wellington.
The trwo families referenced in the question indeed were passengers:
"New Zealand, Archives New Zealand, Passenger Lists, 1839-1973," database with images,FamilySearch (https://familysearch.org/ark:/61903/1:1:FSYV-X44 : 12 December 2014), Christian Hansen, 16 Dec 1872; citing ship Palmerston, Archives New Zealand, Wellington; FHL microfilm .
"New Zealand, Archives New Zealand, Passenger Lists, 1839-1973," database with images,FamilySearch (https://familysearch.org/ark:/61903/1:1:FSYV-N4H : 12 December 2014), Hans Hansen, 16 Dec 1872; citing ship Palmerston, Archives New Zealand, Wellington; FHL microfilm .