One person was reported missing after heavy rain caused river levels to rise sharply in Nelson and a flash flood swept away two cars where people were camping.
A police spokesman said they had received a initial report from a group camping under the Appleby Bridge along the Appleby Highway that one person was missing.
He had since been found and was uninjured.
Nelson City Council said while rain was expected to ease across the region this afternoon, it would be on alert until river levels returned to normal.
Heavy rain hitting the area has caused moderate surface flooding in the city, with one road closed so far.
Council spokesman Shane Davies said the worst of it should now be over.
"We understand that the rain is easing, but often heavy rain in the river catchments can take a while to reach the lower parts of the river.
"We'll be keeping a close watch on things until the river levels have subsided."