Tiny sea creatures called Valella have washed up in their millions at Makara, on Wellington's west coast.

Millions of startling blue jellyfish-like creatures have washed up on beaches around Wellington.

The coast at Makara, west of the city, was thick with them and they had been washing up for days, Haydon Miller said on Sunday.

"You are talking millions."

HAYDON MILLER Velella are about 7cm long, and small stiff "sail" that catches the wind.

While there were some bluebottle jellyfish among them, most of the creatures appeared to be "by the wind sailors", which also go by the name velella.

READ MORE:

* Tiny sailors invade Cable bay

* Thousands of sailors land on Taranaki beach

They are about seven centimetres long, each with small stiff sail that catches the wind and propels them across the sea.

PAUL SPENCE/SUPPLIED Velella washed up at Pukerua Bay, on the Kāpiti Coast, north of Wellington.

More of the creatures were washed up on the beach at Pukerua Bay, on the Kāpiti Coast, north of Wellington.

According to Livescience.com, the creatures are not true jellyfish, but are related to them. They float on the ocean surface and are blown by the wind.

"A Velella's electric-blue body hangs down into the water, with stinging tentacles that capture small prey such as tiny shrimp and plankton."

HAYDON MILLER The coastline around Makara is thick with velella, which have been washing up for days.

The blue colour protects them from the sun's ultraviolet radiation.

"In the ocean, floating snails, sea slugs and sunfish will gobble up the gelatinous creatures for meals.

"Although velella toxins are harmless to humans, it's not a good idea to handle the jelly creatures and then touch your eyes or mouth. The velella neurotoxin might cause itching."

HAYDON MILLER The bright blue colour is believed to protect them from ultraviolet rays as they float on the ocean surface.

Miller said the creatures had been washing up on the Makara coast for a few days, and some had begun to smell.

Strandings of the creature are not uncommon, but it was the first time he had seen them at Makara.

Earlier in October, a swarm of vellella washed up on Cable Bay, near Nelson, and another lot washed up in Taranaki.