The attack at the Club Habitat Holiday Park, which left the girl requiring hours of surgery, is believed to have been sexually motivated.
Inquiry head Detective Inspector Mark Loper said the investigation was progressing well and police were following some positive leads.
"It is still early days but we have maintained a strong focus over Christmas and are making some good progress. We do have some persons of interests and we remain optimistic that we will resolve this investigation.''
Police yesterday said they were interviewing witnesses from as far afield as Wellington.
They would not disclose whether the "persons of interest'' were from Turangi or elsewhere.
"Although we are progressing well we still want to hear from anyone who hasn't contacted us yet and who has information that may assist us,'' said Mr Loper.
The victim and her family were holidaying in New Zealand from Europe.
Her mother was in an amenities block metres from the caravan when the attack happened.
She returned to find the caravan locked, and through a window saw a man on top of her daughter.
She ran screaming for her husband, who was working on a computer in the amenities block, and they found their daughter unconscious on the bed.
The girl's 3-year-old brother was also in the caravan and slept through the attack.
Police said the scene examination was completed on Christmas Eve and the caravan and ute were removed from the holiday park to be returned to the company they were hired from.
A number of items of interest from the crime scene were undergoing forensic analysis.
As of yesterday, $8560 had been donated to the family by New Zealanders appalled by the attack and nearly 600 messages of support had been sent to them.
The hospital was also inundated with Christmas gifts for the girl, some of which were distributed to other sick children in the hospital.
Anyone with information relevant to the investigation can contact the Taupo Police Station on 07 378 6060 or call Crimestoppers anonymously on 0800 555111.
