Rock art in Western Australia's Pilbara region believed to be up to 60,000 years old has been attacked by vandals.

Tourist guide and Ngarluma man Clinton Walker said he had discovered a defaced piece of rock art on the Burrup Peninsula in Murujuga National Park.

"Someone has actually etched into a rock right above where some of the rock art is and wrote: 'go and work for a living'," he said.

The Burrup Peninsula is home to the world's biggest collection of Aboriginal rock art and gained national heritage listing in 2007.

Mr Walker said textas and spray paints had also been used to deface the art.

"There's people spray painting their names on rocks around the Burrup," he said.

"A group of international visitors used a texta to write their names and the date and everything else on the rock art."

Greens MP Robin Chapple said he was shocked and disappointed to learn of the fresh vandalism reports.

He said vandalism and graffiti on the rocks was unacceptable and more needed to be done to educate people about just how precious the art is.

"Vandalism is probably the most detrimental thing that can happen in the short-term," he said.

"Those scratches aren't going to go away because exactly the same way that the carvings remain, those scratches remain.

"So, whoever's done the vandalism out there has left their signature there for a very, very long time."

Vandalism of rock art 'a hobby'

Mr Chapple said he was also aware of vandalism in other areas.

"We know that also on the Yabura Trail, just behind Karratha, there's also rock art that's being defaced," he said.

"It seems to be a hobby or fun for some people to go around literally desecrating what is the world's most important Mona Lisa."

He said the estimated two million carvings on the Burrup Peninsula and in the Dampier Archipelago are of global value.

"What we have here is the largest gallery of rock art anywhere in the world, the oldest gallery of rock art anywhere in the world and the only gallery of rock art anywhere in the world that actually shows the continuing inhabitation of an area and the changes to society over the last 30,000 years," he said.

"It is the only area of the world that has anything like this."

Mr Walker said the graffiti was upsetting and more needed to be more done to educate tourists about just how sacred the sites were to traditional owners.

"It's not just Aboriginal rock art, it's now Australian art," he said.

"We all live in the same place, share the same place, we need to all protect it to make sure it's there for future generations."

Last year the Murujuga National Park was declared a national park in an effort to conserve the area, but the move was criticised by the Friends of Rock Art group who said it fell far short of protecting the Burrup's significant cultural heritage.

They said the park would only cover 44 per cent of the peninsula, leaving the rest open to future industrial expansion.

Researchers from the Australian National University believe the art could be up to 60,000 years old.

There is maximum fine of $20,000 under WA law if a person is found to have defaced rock art.