A dinosaur footprint that has managed to remain on Earth 115 million years has been attacked and damaged by vandals.

The three-toed theropod footprint, discovered in 2006 in Bunurong Marine Park in the Australian state of Victoria, was found damaged by a school tour group last week. Parks Victoria rangers said it would have been done deliberately.

Known as the Dinosaur Dreaming site, the region is an important one for palaeontology. It represents a time when Australia was still connected to Antarctica, and is therefore one of the few high-latitude dinosaur sites in the world.

Because the area is so rich in dinosaur fossils - over 6,000 bones and teeth have been found there - it provides unique data on Early Cretaceous dinosaur diversity, and demonstrates a thriving polar ecosystem.

The footprint in question was made by a theropod, a bipedal meat-eating dinosaur related to the famous T. rex.

When it was initially discovered, palaeontologists made a silicon mould of the print, but instead of excavating it and removing it to a museum, decided to leave it where it was for the enjoyment of visitors to the site.

According to park authorities, the vandals have smashed away parts of the footprint's toes.

"The rock there is reasonably hard, so it looks like it's been hit with a hammer and pieces of the rock around the edge of the footprint have been broken away," Parks Victoria ranger Brian Martin told the ABC.

"For someone to damage it intentionally, you'd have to have a rough idea of where it is because seaweed grows on the rock platform and it looks like a normal rock until you look closely and see the outline of the footprint."

Broken pieces from the footprint have been found in the tidal area, and palaeontologists from Museums Victoria, working with the silicon mould, may be able to restore it to some degree - but it will never be the same as it was, intact for 115 million years.

"It leaves a sour taste in the mouth that anyone would deliberately destroy something that has brought pleasure to so many people over the years," said Dinosaur Dreaming's Lesley Kool.

Parks Victoria is investigating the matter, and is urging people to call 13 1963 if they know anything about the incident.