One person is missing after a fishing boat carrying three people overturned on the Waitaki River.
The incident happened about 11am but the alarm was not raised till several hours later, after two survivors made it to shore then trekked "some distance" to find help.
A helicopter and four jet boats are now searching for the missing person.
A police spokeswoman said emergency services were called to the scene about 2.25pm after it was reported the boat got into trouble on the northern side of the river in the Black Point area, about 53km northwest of Oamaru.
Two survivors made it to shore safely then walked to get help after the fishing boat they were on overturned this morning.
The pair that made their way ashore were transported to Oamaru Hospital in a moderate
condition but their friend was yet to be located.
LandSAR is being deployed from North Otago to assist. St John had also been notified.