Protesters, including one who was abseiling from a bridge, have caused traffic chaos in Adelaide's CBD this morning.
The group from climate action movement Extinction Rebellion protested near the Adelaide Convention Centre, where the Australian Petroleum Production and Exploration Association (APPEA) conference is being held.
The protest caused the Morphett Street bridge to be blocked and halted trams along nearby North Terrace.
Traffic was diverted in the city's west end, but the diversions were later lifted and traffic was starting to return to normal by 9am.
A woman who was abseiling from the Morphett Street bridge was safely brought down just before that time.
According to Extinction Rebellion South Australia, the woman had been suspended from the bridge for more than an hour-and-a-half.
SA Police said a 69-year-old Willunga woman was arrested for obstructing a public place.
Extinction Rebellion SA's Mary Heath apologised for the inconvenience to the public, but said they took "civil disobedience" action because "our leadership is not acting" on scientific advice regarding climate change.
"What is mostly happening here is disruption, which we understand is inconvenient," she told ABC Radio Adelaide's Stacey Lee and Nikolai Beilharz.
"But I think every Australian understands that floods, and droughts, and bushfires are also very inconvenient and they are putting many more lives at risk all around our country."
Commuters expressed their frustration at being stuck in lengthy delays during the morning commute.
Dean, who works at a hospital intensive care unit, said he left work early this morning after his night shift and became stuck at War Memorial Drive.
"I've been awake for almost 24 hours," he told ABC Radio Adelaide.
Mandy, who also works in intensive care, said her commute home after night shift took an hour and a half, instead of the usual 30 minutes.
Danny pointed out the extra time people spent in their cars during the traffic delay would have contributed more fossil fuels than usual.
"It's just contradicting her protest," he said.
James said the protest was "galvanising the public against them, the public, the vast majority of which are for climate change action".
"So as someone that cares about climate change and what's going on, I'm just really angered by what they're doing because they're actually working against the cause," he said.
Another commuter, Natalie, said her child missed a doctor's appointment this morning after they became stuck in the traffic chaos along Port Road, which turned the journey into a three-hour trip.
"They've ended up having to try to do the whole appointment over the phone," she wrote on ABC Adelaide's Facebook page.
Transport and Energy Minister Tom Koutsantonis, who spoke at the oil and gas conference this morning, said while people have a right to protest outside the conference, the actions this morning were "reckless".
"These childish stunts do nothing but turn people off the hard task of decarbonisation," he said.
"They've chosen to protest on a feeder road that leads to the Royal Adelaide Hospital ... the inconvenience they are putting on the people of the South Australia is by far probably the most insulting thing they've done."
Opposition energy spokesperson Stephen Patterson said the conference itself was "aiming to do" what the protesters were talking about.
"The topic of that [oil and gas] conference is how that oil and gas industry is going to accelerate towards net zero," he said.
"... We should be supporting that, not protesting causing massive inconvenience."