More then 20 police were last night searching for the man who is alleged to have broken into the vehicle where the pair slept yesterday morning.
The man, who had his head covered, entered the vehicle at the Five Mountains Holiday Park in Clifden Rd about 6.40am, the officer in charge of the case, Detective Sergeant Dave Nelson, of Invercargill, said.
He threatened the pair, a 25-year-old man and a 22-year-old woman, at knifepoint and sexually assaulted the woman.
He then demanded cash and ran off after they gave him a substantial amount.
Police believe a second man standing outside the vehicle was not involved in the attack.
Det Sgt Nelson said because the alleged attacker's head was covered, police did not have a detailed description of him.
Police were also investigating the burglary of a Tuatapere property a few doors along from the holiday park, he said.
"We are in the early stages of this investigation and following a number of leads."
A shop assistant at the Tuatapere Four Square said the locals had wondered what was happening all day yesterday, as dozens of police cars and more officers swarmed into the town and cordoned off the holiday park.
"They [the police] interviewed us, but they wouldn't even let on what had happened then; just asked us if we'd seen the Dutch people or anyone suspicious around town."
It was not until 4.30pm that police released the first details.
The shop assistant said she had served the couple on Wednesday.
Tuatapere Community Board deputy chairman Les Johnston said residents would be horrified when they learned what had happened.
"We certainly would never expect anything like that to happen here.bThis sort of thing is not good for us; it is not good for any community.
"We are trying to be a nice happy little community . . .This is just horrible."
In a more general sense, the incident was also not good for the town, which was trying to promote itself as a tourist destination, he said.
Tuatapere had changed in recent years, Mr Johnston said.
"Fifty years ago, I knew everyone here.nI used to drive the school bus and I knew every kid. Now, I don't know 50% of the people living here.
"There's a lot that move on quickly; only come here for summer work or only a few years. The town's quite different."
Det Sgt Nelson said police would like to hear from anyone who saw suspicious activity, people or vehicles in the Tuatapere area overnight on January 14 and 15.
People with information should contact their local police station or Detective Sergeant Dave Nelson at Invercargill police on (03) 211-0400.
The couple are being cared for by Victim Support and Invercargill police.
