The 12-metre replica on display in the New World Plaza at the New World Centre until December 26 is based on fossils discovered last year by a National Geographic team in the sub-Saharan desert in the Republic of Niger.

Palaeontologist Paul Sereno, who led the team, knew it was no ordinary dinosaur when they uncovered the two-metre-long jaws.

'We had never seen anything like it. The snout and teeth were designed for grabbing prey - fish, turtles and dinosaurs that strayed too close,' said Dr Sereno, from the University of Chicago in the United States.

Dr Sereno said although scientists had known for decades about the creature - Sarcosuchus Imperator - little had been known about its anatomy, size and life span.

The SuperCroc has more than 110 teeth, including a row of bone-crushing incisors. Its eye sockets are tilted upward, which helped it hide underwater while scanning the water's edge.

Dr Sereno believed the SuperCroc roamed the Earth about 110 million years ago and had become extinct because of a change in climate that dried up the sub-Sahara before the dinosaurs disappeared 65 million years ago.

Dr Sereno is a dinosaur hunter extraordinaire. In the past decade, he has either found or helped identify several species, including a shark-toothed carnivore in Morocco far bigger than Tyrannosaurus rex, and an Andespredator - little bigger than a dog - from the dawn of the dinosaur era.

Construction of the clay and fibreglass replica of SuperCroc took more than a year. It arrived in Hong Kong from Sydney.

A two-hour programme on the discovery of the SuperCroc will air on the National Geographic Channel Asia at 9 pm on December 9.