A Nelson woman who said she was sexually assaulted while hitchhiking in the Maitai Valley last month fabricated the complaint, police say.
The 21-year-old woman said she was hitchhiking from Richmond to Nelson on February 15 when she was picked up by a man in his 70s.
She said he locked her in the car and drove to the Maitai Valley near Nelson where he sexually assaulted her.
A police investigation has revealed the complaint was fabricated.
Detective Senior Sergeant Wayne McCoy said such complaints received priority and significant time and resources had been tied up investigating it.
"To receive a false complaint is disappointing on several fronts. Resources that could have been used investigating other genuine complaints had been tied up and on top of that the public of Nelson have been led to believe they should be fearful for their safety," said Mr McCoy.
The woman would be summonsed for making a false complaint to police.