South Australia will ramp up fines and introduce possible jail time for disruptive protesters who potentially risk public safety.
Responding to climate change action in Adelaide this week, the state government has rushed into parliament legislation increasing the maximum fines for public obstruction from $750 to $50,000 or a three-month prison sentence.
The bill has the support of the Liberal opposition, which proposed similar changes, ensuring its swift passage.
Premier Peter Malinauskas told parliament there were few things more important than the freedom of association and the ability to protest peacefully.
"It is an essential formulation to the way we govern ourselves. It's an essential component of the functioning of our democracy," he said.
"But that is a very different thing to someone or a group of people who conduct themselves in such a way that puts other people's safety at risk."
The government's move came after three days of protests by members of Extinction Rebellion, including the action of a 69-year-old woman on Wednesday who abseiled over a city bridge and disrupted peak-hour traffic for about 90 minutes.
The group said her action was to give a "life or death message" to delegates attending the nearby Australian Petroleum Production and Exploration Association conference at the Adelaide Convention Centre.
Opposition Leader David Speirs said it proved costly for businesses and there were reports people had been delayed attending appointments at the nearby Royal Adelaide Hospital.
"These types of protests are getting out of control and we are sick and tired of seeing groups and individuals receive nothing more than a slap on the wrist," he said.
"We believe in every South Australian's right to protest, but in a peaceful way that is respectful of those who chose to go about their daily lives.
"What we saw yesterday from Extinction Rebellion was outrageous and unacceptable."
Greens MP Robert Simms said such legislation to curtail the right to protest was "chilling".
"Draconian anti-protest laws were rushed through state parliament in NSW. It's very alarming to hear that South Australia may be next," he said.
"The right to peaceful protest and civil disobedience are fundamental to our democracy."
In Thursday's protest, activists targeted the Santos headquarters in Adelaide, allegedly throwing paint on the building, with four people arrested.
A 68-year-old Victorian woman and a 49-year-old NSW woman were charged with property damage and marking graffiti, a 50-year-old Victorian man with property damage, and a 66-year-old Adelaide man with disorderly behaviour and property damage.
Acting Superintendent Paul Sinor said police had maintained a professional and patient approach to the protest action this week but blatant disturbance to the public peace and property damage would not be tolerated.
