"At the time this happened, there was a green rental van parked nearby. The occupants of this vehicle may have witnessed this incident and police would urge them to come forward," Mr Wilson said.
"The couple from the rental van are described as a male with a blue backpack and a female with a red backpack.
"The female was blonde. It is believed this couple were possibly French tourists."
He said police wanted to hear from anyone who might have been in the Kuirau Park area at the time of the attack and witnessed the incident, or anyone in the community who might have information.
They could contact police on (07) 348 0099 or call 111 if it is was emergency.
There were two sexually motivated attacks in Kuirau Park last year.
A woman in her 40s told police that in August she was attacked by two men when she walked through the park in the early hours of the morning.
At the beginning of last year, a 15-year-old was followed into the public toilet at the park by a man in his 40s, who then locked her in and sexually assaulted her.
Polish tourist Roman Skorek was murdered in the park in January last year after he allegedly made sexual advances towards a group of young men.
