Police are currently searching for a man in water near Mornington Pier.
It is understood a small boat, with two people onboard, overturned around 1km from the shore.
Emergency services were called to Schnapper Point Drive about 11.15pm.
One man was rescued by another boat.
He was assessed by paramedics and was not seriously injured.
The second male occupant, believed to be in his 20s, is outstanding.
An immediate search commenced involving Water Police, Air Wing and Uniform officers, with assistance from HEMS, Life Saving Victoria and the coast guard.
Anyone who witnessed the incident or has information is urged to contact Crime Stoppers on 1800 333 000 or log onto www.crimestoppersvic.com.au
