You are not permitted to download, save or email this image. Visit image gallery to purchase the image.
Guide Shaun Wilson, who studies orca at the University of Otago, said cruise passengers saw a pod of 10-12 orca on the last cruise of the day.
The apex predators are usually seen in the harbour around five or six times a year, but in much smaller pods.
"It was great to see so many.
"Everybody was very excited, particularly when they found out it only happens a few times each year.''
The passengers were extra lucky sighting a small pod of Hector’s dolphins - which are among the smallest dolphins in the world - at the start of the trip, before seeing the Orca which are the largest.
The orca were spotted a few hundred metres from the light house at Taiaroa Head and the cruise followed them into the harbour.
Although orca prefer deeper waters, Mr Wilson said they often spent time socialising in Pilot Bay by the penguin and albatross colonies.
It is not an unusual time of year to see orca, but he had not seen this specific pod in the harbour.
"Orca tend to show up when it suits them.''