Police have suspended the search for a boat reported to have been swamped by water in the Cook Strait last night.
The call for help was made about 10pm on Monday reporting a small boat was taking on water about 3 nautical miles from Karori Rock.
Wellington District Search and Rescue Coordinator Sergeant Jonathan Westrupp said the person indicated their boat was taking on water with two people on board.
"They failed to respond after several further transmissions and a search was immediately activated and multiple vessels were deployed to the area, Westrupp said.
"We've found no objects of interest in the strait or during searches of the shoreline or boat ramps, and no boaties have been reported missing or overdue."
Ferry passengers on board the Interislander Kaiarahi helped in the search for the boat.
Police paused on Tuesday morning to determine "the nature" of the mayday report before continuing efforts.
Kaiarahi passenger Tupoki Wairau-Hunter said they were told the sailing would slow down to search as it approached Wellington just after 11pm on Monday.
People went on deck and were encouraged to let the crew know if they spotted anything.
Wairau-Hunter said conditions were mild with a "bit of a swell" and lights from up to seven other ships involved in the search could be seen from the ferry.
The sailing was delayed by a couple of hours but Wairau-Hunter said people were happy to help and concerned about the fate of the boat's crew.
An interislander ferry joined the seach for a missing boat on Monday night. Photo: Supplied
Videos on social media showed search lights being used as the Interislander combed the area in the dark.
"Boats from Police, Coastguard Wellington, CentrePort, Wellington Airport Fire and Rescue, and the Interislander searched the area until 2.30am, but no debris was found," police said on Tuesday.
"A Search and Rescue team and Police also checked along the shoreline and boat ramps, but nothing of note was located."
Search and rescue also canvassed the shoreline.
A spokesperson from Seaworks Ltd said its their cable zone patrol ship Sea Patroller was also called in to assist - shortly after the mayday was reported - but was stood down after a little over four hours.
Bluebridge Cook Strait said Strait Ferronia crew saw something in the water but the object was not a boat.
Westrupp said police were making enquiries into the distress radio transmission to determine its source and veracity.
Police are asking the public to tell them if they notice anything unusual in the Cook Strait area or become aware that someone is overdue.
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