Protesters say they will lay a complaint of excessive force against police after a man was injured and bloodied after going to the aid of his 70-year-old father who was jumped on by four officers.
Police moved on the blockade at James Price Point early on Tuesday morning and began removing people sitting on the road and taking them to police vehicles.
Protesters have maintained the blockade, about 60km north of Broome, for a month, preventing Woodside Petroleum contractors from accessing the site to carry out geotechnical studies.
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The protesters, made up of traditional owners, environmental activists and local residents, oppose plans to build a $30 billion gas precinct on the site.
One protester, who did not wish to be named, told AAP that police made 12 arrests in the morning and 10 more after they made a determined push against protesters after midday.
Police officers formed in a circle called a "bubble" and moved against protesters who numbered around 100, with more arriving from Broome, he said.
"There was some police brutality," the protester said.
"A 70-year-old man was jumped on by four police officers. His son tried to help him and he was injured. The guy was covered in blood."
The protester said protest organisers would make a complaint against police that they had used excessive force.
He said one protester had tied himself to a bulldozer at the site and police were cutting him free.
There were about 80 police at the site but protesters were holding their ground, the protester said at 3pm (WST).
Those arrested have been taken to the Broome police lock-up.
The protesters maintain that Woodside does not have the necessary environmental approvals to clear land at the site.
Extra officers were flown to Broome on the weekend for the police operation.
WA Police Minister Rob Johnson told reporters in Perth that he supported police who had the right to arrest people who broke the law.
Woodside Broome operations vice-president Niegel (Niegel) Grazia said in a statement that the company had all the necessary consents and approvals to conduct its geotechnical studies.
