Caltex regional manager Ankur Patel told the Herald there were two trees in the store and it wasn't until the next morning they realised one was gone.
"One of the kids took the small Christmas tree - we had two, one big, one small - and the kids just picked up the small one and walked out," he said.
"They came around 9.30 and we only had one staff and he was dealing with the queue of customers. We didn't realise the tree was gone until the next morning."
It occurred after they were abusive towards staff of a Hamilton Burger King yesterday.
"Their disorderly behaviour at Burger King prompted the managers to call police, and we went with police, knowing the background of these people as obviously they hit the media before yesterday."
Auckland Mayor Phil Goff has waded into the thick of things again after calling the group "a bunch of a***holes" earlier this week on bFM.
Today, the Mayor said on Facebook it was "justified" for members of the public to tell the tourists to go back to were they came from.
"Telling visitors to NZ to go home is pretty unusual behaviour by Kiwis but in the case of tourists from Liverpool who have been creating mayhem around Auckland it's totally justified," he said.
"They came to public attention after leaving their trash on Takapuna Beach and abusing those who told them to pick it up.
"I hope authorities can hold them to account for this and I'm encouraging it. And getting rid of them out of the country as quickly as possible."
Earlier today, 26-year-old Tina Maria Cash pleaded guilty to stealing energy drinks, a rope and sunglasses from the service station on two separate occasions.
The court heard that Cash stole a can of Red Bull from a Caltex service station at Albany on December 31.