Nobody knows who is responsible for the giant figure - a man with what appears to be a bird's head - but aborigine leaders say it amounts to "graffiti" on a sacred tribal site.

The shape, which is carved into the dust near Finniss Springs in South Australia, was discovered last week by residents of the tiny settlement of Marree.

It is believed to be a depiction of an aboriginal warrior and has been christened Marree Man.

The giant carving is close to the town of Marree in South Australia

Instructions about how to find it were faxed anonymously to a hotel in the town, which is 300 miles north of Adelaide.

Almost invisible from the ground

The figure is difficult to discern from the ground but is clearly visible from the air and seems to be the work of a professional.

David Rathman, head of South Australia's Aboriginal Affairs Department, said local aborigines feared sacred ceremonial sites may have been disturbed by the carver.

He said: "I imagine it's the appearance of this particular graffiti on their land that has made them upset."

Raelene Warren, spokeswoman for Dieri Mitha Council which represents one of several aboriginal clans in the region, wants to stop tourists driving to or flying over the site.

'Exploiting aborigine culture'

She said it was "exploiting our culture and our dreaming."

Aboriginal beliefs are based around tribal links to their ancestors and the land and dreams are an integral part of their belief systems.

Six aboriginal clans had laid claim to the region long before the figure was made.

Experts say whoever carved the figure must have used Global Positioning Satellite technology and a large plough-type machine.

One said: "Somebody has obviously thought it out, they must have known they could fit it in on that area and planned it out."