Hansen said he was concerned "this might not be a one-off" and that the penguins may have been "smuggled".
"The very next day another penguin was found dead floating nearby and it appears it may have died from a head injury.
"We have no idea where these birds are being taken to and we are seeking CCTV footage from the surrounding area and hoping members of the public may be able to come forward with further information."
Hansen said DoC was working with other government agencies and had interviewed a number of people about the issue.
"This is particularly disturbing as it is a very vulnerable time for these wee penguins/kororā.
"They moult from January through to March and stay in their burrows for protection.
"They are nocturnal animals, and the time this offence occurred in the evening, further suggests the poachers knew exactly when best to target the birds."
Little blue penguins are protected wildlife and people found committing offences may receive imprisonment of up to two years and fines of up to $100,000.