A search and rescue operation on the West Coast was pulled down following the reports of a person sweeping the swollen Haupiri river.
A police spokeswoman said she had been waiting for the call for a short time before 11:00 pm.
"Emergency services, a woman reportedly went to the river 7.59pm." Said.
"A search in the area this evening has failed. The search will continue in the morning."
In the early hours of this evening, a spokesman for the Greymouth Police said they had responded to a man's reports.
"Emergency services and members of the public at the scene and looking for the missing person," they said.
The river crosses Gloriavale, the isolated Western Coast Christian community.
The area rained from midnight on Wednesday, which continued throughout the day and was generally heavy.
NIWA, yesterday and yesterday afternoon between 14:00, the West Coast and the Southern Alps more than 300mm 'in the area recorded the rain.
The Ivory Glacier took a rain of 391 mm, about 50km, while flying from Haupiri – more than Clyde, seen in Cromwell and Alexandra 2017
Rain destroyed a group of students in a cabin in Mt Aspiring National Park and saw students at a West Coast school evacuated by the police.
Elsewhere, after heavy rain and flooding, a bridge collapsed in the Goat Creek on the State Road to the east of Otira.