Conservationists were right to block the Hollywood movie Stealth from shooting in a Blue Mountains wilderness area, says a prominent filmmaker.

John Weiley, a former president of the Screen Producers Association and maker of an IMAX film on the Blue Mountains, said yesterday that the damage caused by a crew at the ancient Peruvian city Machu Picchu showed the risks from filming in sensitive locations.

While shooting a beer commercial for an American company in 2000, a falling camera crane chipped a sacred sundial.

"Filmmaking is not a charity," Weiley said. "They're doing it to make money. Whereas if you've got something that's seriously precious, once it's busted, it's busted."

The makers of Stealth, the $130-million action-adventure movie that has been shooting around Sydney, planned to film in the Grose Wilderness for two days. They have been forced to change their plans after the Land and Environment Court, in a case brought by conservationists, decided filming breached the legislation affecting national parks.

Weiley said Americans were just as protective of their national parks. "If you try to shoot in Yellowstone National Park, you'll go through just as many hoops as you will here," he said.

The State Government plans to introduce legislation today allowing filming in national parks for commercial purposes when strict environmental conditions are met.

Weiley supported the move, so long as filming was supervised.

"It's absurd to say you can't shoot a film in a national park," he said. "But it has to be intelligently and tightly supervised, which films crews are used to. Try and shoot in Pitt Street. There are a million restrictions and restraints everywhere you go."

Filming of Stealth, starring Josh Lucas and Jessica Biel, is expected to continue in the Blue Mountains until Saturday, returning to a location used for the days lost in the Grose Wilderness.