Freak waves on Wellington's south coast have left a person in hospital and forced residents to evacuate their homes.

Photo: Supplied / Katie Hecker Scheid

A big southerly swell is caused 6m waves to crash onto the road between Breaker Bay and Ōwhiro Bay.

About half a dozen homes were evacuated late this morning as the waves crashed across the road and into garages and houses.

Wellington Free Ambulance said one person had to be rescued after being swept out to sea and is now in a moderate condition in hospital.

Photo: Supplied / Grant Maiden

Wellington City Council said the water caused damage to garages, cars and left debris on the roads.

Its spokesperson, Richard Maclean, said council contractors and emergency services were on site to help clear the roads and support residents.

Photo: Supplied / Grant Maiden

Motorists and pedestrians were asked to avoid the south coast. People are being warned not to go and have a look.

The section of Breaker Bay Rd and Moa Pt Rd between Mantell Street in Seatoun and Cochrane Street, Lyall Bay, is closed.

Photo: Supplied / Donna Drinkwater

Wellington coastal residents watched with amazement as the huge waves crashed into their properties this morning.

Tayla Philpott filmed the waves crashing into her house.

Photo: Supplied

Philpott said she was luckily on the third storey, and not near the waves.

"So it was coming right up at our house - the water went through our garage but the worst of it is really at the top of the street - the waves sort of just carried on right up the bay," she said.

She said there was a lot of debris.

"A lot of drift wood - there's a shipping container that sort of moved out onto the middle of the road."

Photo: RNZ / Caitlin Cherry

Another resident, Jemima Bullock, who lives between Island Bay and Ōwhiro Bay, said the waves sounded dramatic and harsh from early this morning.

Bullock said it caught curious onlookers and dog walkers by surprise.

"We saw a few dog walkers get into trouble - so we yelled if they needed some help - but most of them just got wet really and cleared the way and then at that point I put two messages on local Facebook pages saying 'don't come down, it's not that safe'," she said.

Photo: RNZ/Caitlin Cherry

MetService forecaster Andy Best said the waves had now peaked.

"High tide was just before midday - so the tide is now going down and the actual forecast for the maximum wave is receding because those waves are actually moving to the north east," he said.

Police said they, and the council, were clearing the debris, cleaning roads and assessing the damage.

The road between @sprucegoosewgtn and Moa Point is closed to most vehicles due to water and debris on the road. @lyallbaynz. Thank you to the teams from @WgtnCC for keeping an eye on the coast road. pic.twitter.com/oZraaafiVU — Wildbaynz (@WildBayNZ) April 14, 2020

Clean-up time! Doing the mahi with #IslandBay local Jim Moriarty on #Wellington’s south coast - as we korero with Tangaroa + Tāwhirimātea to ask for kindness at this time! PS. Like the social distancing? @WgtnCC @fultonhogan



#Wellington #COVID19nz #PaulEagle❤️Rongotai pic.twitter.com/oFIkrLAaXo — Paul Eagle MP (@pauleaglenz) April 15, 2020

Yeah not so fun any more pic.twitter.com/G9KabQ7R8K — Nikki Macdonald (@Nikki_Macdonald) April 14, 2020