Scientists believed they have found 70 million-year-old dinosaur footprints -- the first ever found in New Zealand.

The prints are spread over six locations in northwest Nelson in the South Island, with up to 20 at one site, Radio New Zealand reported on Saturday.

GNS Science sedimentologist Greg Browne has been studying the marks for years and believes they were made by sauropods -- plant-eating dinosaurs with long necks and tails, up to 6 meters in length and weighing several tonnes.

He said the prints were made in beach sand, then probably quickly covered by mud.

"It's just a chance occurrence that they are there in the first place -- almost always they'd be destroyed. In that sort of environment you've got tides, winds and currents, so the likelihood of any footprint being preserved on a beach is virtually zero," Radio New Zealand quoted him a saying.

The footprints also provide the first sign that dinosaurs once roamed the South Island.

New Zealand paleontologist Joan Wiffen found the first evidence that dinosaurs had inhabited New Zealand after discovering fossil bones in Hawke's Bay in the North Island. However, no bones have yet been found in the South Island.

In 1975, she found a fossil bone that turned out to be part of the vertebra of the first known terrestrial dinosaur from New Zealand -- a theropod, a carnivorous creature 7 meters long and 2 metres high that walked on two legs.

Browne has made silicon molds of several of the prints and his paper describing the discovery will appear in the New Zealand Journal of Geology and Geophysics this week. 

VietNamNet/Xinhuanet