HEAVY DUTY: Big Ben’s fleece is heavier than that of previous world champion Shrek.

Big Ben is bigger than Shrek - unofficially.

When Mike Lindsay first saw four merino sheep nestled in a corner of his 2500-hectare Twizel station he thought they looked like giant mushrooms.

"Because they carried so much weight, when they moved they almost seemed like ships bobbing in the ocean because you couldn't see their legs," he said.

They were recaptured on the slopes of Mt Ben at Omahau Hill Station after about six years of being separated from their flock.

The most impressive of the bunch was dubbed "Big Ben".

On Saturday, shearers set about seeing just how big he was by attempting to set the first Guinness World Record for the heaviest single fleece taken from a sheep.

Big Ben's fleece, shorn by former world champion shearer Tony Dobbs, took 25 minutes to take off.

"It was very slow going because of the sheer weight of wool that was pulling against his skin," Lindsay said.

"We had to have someone else hold the wool so it didn't rip the sheep's skin."

When the job was complete the fleece weighed in at 28.9 kilograms.

The fleece of Shrek, the merino who made international headlines when he was found in 2004 after avoiding being caught and shorn for six years, weighed in at 27kg.

However, this weight was never submitted to Guinness World Records. An average merino fleece weighs about 4.5kg.

There were celebrations yesterday as Big Ben's fleece was weighed.

The event was used as a fundraiser for a new Twizel medical centre. The fleece will be turned into a baby's shawl, which will then be auctioned to raise money for the centre.

"We are hoping that, once it's officially announced we have got a record, it might draw some attention and bring someone out of the woodwork to buy it [the fleece]," Lindsay said.

The shorn sheep were bright and happy, Lindsay said yesterday.

But it had been a wet morning in Twizel so they were being kept indoors and were also given coats to keep them warm after the shock of being shorn.