A far north Queensland crocodile has reclaimed the title for the world's largest in captivity.

'Cassius' the croc weighs more than a tonne and measures 5.48 metres.

He lives at a crocodile farm, Marineland Melanesia, on Green Island, and held the title until the capture of a 6.17 metre croc, Lolong, in the Philippines in 2011.

However, the park's Billy Craig says Cassius has taken back the crown after Lolong's death on the weekend.

"We changed the sign to the largest crocodile in captivity in Australia, so I guess we can now just remove the Australia part and put it back to the whole world," he said.

He says while he is happy for Cassius, he is sad to hear of his rival's death.

"We did know that he was quite a young crocodile in comparison to our croc," he said.

"We think he was probably about 50 to 60 years old, which is 50 years younger than Cassius.

"Cassius we think is 100 at least, probably 110, so it was an interesting thought to think he's got another 50 years' growth in him.

"If he's already six metres, what's he going to be like in 50 years?

"There was so much interest in Lolong and the town that it's a massive shock, a loss to them.

"They're saddened by the death of Lolong and saddened by the potential loss of tourism that they're going to face."