One person has died after being swept down the Waikato River after their boat overturned.
Four people were on the vessel at Ngahinapouri Island at Port Waikato when it overturned about 3pm today.
Three people were rescued.
And a call for help broadcast on an emergency radio channel this afternoon sparked a search on Lake Wakatipu.
A Coastguard boat and a number of private vessels have been searching but the Queenstown police cannot confirm a vessel is in distress.