Senior Constable Scott McLeod said police wanted to talk to anyone who might have seen the victim and offender in the vicinity of Paora Hapi and Kaimanawa Sts just before midnight.
The victim was wearing a baseball cap, a white t-shirt and brown-coloured trousers.
"This was the evening of the Bledisloe Cup game in Brisbane," McLeod said.
"The game ended shortly before the assault occurred so we know people were out and about having watched the game in central Taupō."
Anyone who might have information that can assist is asked to contact police on 105 and quote file number 201108/1962.