The Disrupt Burrup Hub group say they were en route to shoot a documentary with an international film crew when they were stopped and searched by police on the side of the highway about 4.30am on Tuesday.
Campaigners continued to film as police seized phones belonging to activists, requested passwords which were refused and issued move-on notices prohibiting access to the Burrup Peninsula for 24 hours.
"We have been aware of police surveillance and infiltration within our campaign and anticipated a police operation to intercept us," a spokesperson said.
Woodside plans to expand its Burrup Hub in the Pilbara in Western Australia. (Aaron Bunch/AAP PHOTOS)
The group said it was planning to "film footage as the sun came up" and no direct action against the Woodside site was planned.
"The only reason provided by WA Police was that one campaigner was wearing a Disrupt Burrup Hub T-shirt," the spokesperson said.
"We look forward to a full investigation into how and why police have tried to disrupt Disrupt Burrup Hub in such a calculated, malicious way."
The group's lawyer Zarah Burgess said the incident was an abuse of power by WA Police and the state government had "capitulated" to the interests of a fossil fuel corporation.
"We have no information about the legal basis on which the mobile telephones were seized, and so the lawfulness of these seizures is very much in question," she said.
WA Police confirmed that four men and a woman were issued with move-on notices and a number of phones were seized as part of an ongoing investigation.
The Burrup Peninsula, in WA's Pilbara region and known as Murujuga to traditional owners, contains the world's largest and oldest collection of petroglyphs.
Disrupt Burrup Hub claims Woodside's operations in the area and its proposed expansion form the biggest new fossil fuel project in Australia and could produce billions of tonnes of carbon dioxide by 2070.
It has carried out protests against Woodside this year including the release of stench gas at the company's Perth headquarters in June, forcing the evacuation of about 2000 staff.
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