Boat owners have been left devastated after a suspected tornado ripped through Auckland's waterfront yesterday.
Andy and Viv Stewart own a 60ft catamaran called Rosella which flipped upside down during last night's wild weather.
"When we got the call saying Rosella, our catamaran, was upside down, we didn't believe it," Mr Stewart said.
"I came down yesterday and checked all the lines and made sure there was double lines on due to the stormy weather around, but they reckon we had winds through here over 200kmh, so it just tore everything to bits and took off."
"The winds flipped it vertically and it went straight over," Mrs Stewart said.
Mr Stewart told 1 NEWS he has never seen anything like it.
"The ferocity of the storm is like something we've never seen before, we've crossed the Tasman in this boat and then sitting here in the marina we get a storm come through and do that, we're pretty devastated."
The Coastguard issued a warning last night to mariners saying they need to be extremely wary while the debris is cleaned up.
"Strong localised thunderstorm gusts caused significant damage to moored vessels, upturning and sinking large recreational vessels in and around Westhaven Marina and casting adrift the commercial Great Barrier Island car ferry from Wynyard Terminal," Coastguard duty officer Hemi Manaena said in a statement.
"Several large portacom units, shipping containers, cars and pylons were also lost into the harbour," he said.
NIWA says this weather isn't over yet, with more thunderstorms expected from about 6pm today.