Wellington - Scientists examining the most perfect example of the largest squid ever caught uncovered on Wednesday the biggest eye in the animal world - measuring 27 centimetres across.

"It is a truly phenomenal eye," Steve O'Shea, New Zealand's leading expert on squids, told Deutsche Presse-Agentur dpa as he studied the 495-kilogram colossal squid slowly thawing after being kept frozen since it was caught in Antarctic waters 15 months ago.

And Eric Warrant, a Swedish professor who flew to New Zealand for the occasion, said the eye was "truly amazing" and, when the squid was alive, the organ was probably the size of a football.

"These are without doubt the largest eyes that have ever been studied - and probably among the largest eyes that have existed during the history of the animal kingdom," Warrant said.

The squid's other eye was damaged when the monster of the deep was hauled up from a depth of about 1,500 metres while clamped onto a big toothfish hooked by a New Zealand fishing boat in February last year.

O'Shea said the massive creature's beak was "extremely thick and hard and could crush the vertebrae of any 2-metre-long toothfish with no difficulty."

He said the examination indicated that the colossal squid, Mesonychoteuthis hamiltoni, could grow up to 750 kilograms.

Up to 2,400 viewers at a time have logged in from around the world to a webcast from the marine laboratory of New Zealand's national museum in Wellington to watch as scientists from Sweden and Japan joined O'Shea and his assistants in examining the defrosting giant.

Pledged to keep the creature intact so that it could eventually go on display for Te Papa museum visitors to marvel at, O'Shea ruled out dissection and inserted an endoscope into its stomach to view the contents.

O'Shea's assistant Kat Bolstad said the colossal squid fed largely on toothfish, grabbing its prey with razor-sharp swivelling hooks on its tentacles and slicing it into small pieces before eating it.

Despite its size, the colossal squid remains vulnerable to bigger giants in the deep, being the main diet of sperm whales, which Bolstad said are known to eat several a day.

The scientists began preserving the creature with formalin as it thawed to prevent it from deteriorating. It is to go on display at the national museum later this year. (dpa)