A police spokeswoman said they were "not in a position to share the location for the planned event".
Last year an unofficial Wellington College ball organised by students without the school's permission left 37 students requiring treatment for alcohol-related issues, and 11 injured.
Former Wellington College student Hugh Soper is this year's ball organiser and he posted on Facebook that tickets were on sale for the event, but it was not associated with any school, Fairfax reported.
"Location is in central Wellington and full disclosure of the location will be said [on Friday] night," the post read.
A ball had been scheduled to take place in the James Smith Corner basement in late September, but that was scrapped after police said the venue's licence meant every attendee under the age of 18 would need to be accompanied by a parent.
Wellington College headmaster Roger Moses told Fairfax that the school "completely dissociates itself from any private function organised by any individuals, whether they be parents or students". The school has not had a ball for about 25 years.