The man was also described as wearing a navy blue T-shirt with white patches on it, black sunglasses, and dark coloured ¾ shorts.
Police said they believe he left the area in a vehicle after the assault and were appealing for information to identify the man and his vehicle.
The spokeswoman said a number of people had already made contact with information.
Tourism Bay of Plenty head of marketing Kathrin Low said they were sorry to hear of the assault.
Safety and the comfort of knowing Tauranga's natural attractions were easily accessible was important.
"Infrequent occurrences such as this hopefully won't impact the destinations reputation."
Mount Mainstreet manager Ingrid Fleming said it was a very unusual thing to happen given the large number of people that go up and down every day.
Anyone who has information about this incident is asked to contact the Tauranga police on (07) 5774300. Alternatively, information can be provided anonymously through Crimestoppers on 0800 555 111.