Police will use new anti-protest legislation to prosecute 10 people arrested during peak-hour climate change protests in Sydney.
Sydney's morning commute descended into chaos after protesters blocked southbound lanes in the Harbour Tunnel, sparking major traffic jams.
Blockade Australia protesters also marched through Sydney's CBD where a car rammed into several people wearing high-vis gear, causing chaotic scenes on the corner of Bridge and Phillip streets — although no one appeared to be seriously injured.
NSW Acting Assistant Commissioner Paul Dunstan said it would take some time to interview the protesters who had been arrested and he expected there would be more arrests to follow.
"Police will be reviewing CCTV following this morning's unlawful activity and it is likely other people will be identified and arrested.
"Those people will be charged with the recently introduced legislation from the government relating to the obstruction of major roadways."
Under the legislation passed in April, people protesting illegally on roads, rail lines, tunnels or bridges can be fined up to $22,000 and jailed for a maximum of two years.
The new laws were introduced after Blockade Australia activists staged a string of protests in March blocking access to Sydney's Port Botany, the busiest container port in the country.
Spokeswoman for the climate activist group Sally-Anne Brown said the purpose of today's rally was "to disrupt the economy."
"I got the impression a lot of people supported our call for climate action," she said.
"It is terrifying to act out against these police powers that are being passed but it is necessary to disrupt people's sense of comfort around the existing system because it is damaging our planet."
Acting Assistant Commissioner Dunstan said the behaviour of protesters was "nothing short of criminal".
"There is a highly recognised way to protest. Notify the police and submit what we called Form 1. There is a way to do it but the way they did it today was totally unacceptable," he said.
Police said they would also be examining aerial vision of a car driving at speed into protesters.
"I am aware of that incident and we will investigate that," Acting Assistant Commissioner Dunstan said.
One woman was arrested after allegedly locking herself to the steering wheel of a car and parking it across the entrance to the Harbour Tunnel, which is one of only two ways to cross the harbour.
Police described the woman's actions as "incredibly dangerous".
"The woman who stopped that car at the entrance to the Harbour Tunnel placed herself at risk, placed members of the public at risk and placed her rescuers at risk," Acting Assistant Commissioner Dunstan said.
Motorists were diverted to the Harbour Bridge before the tunnel finally reopened about 9.15am and traffic has since returned to normal.
About 60 protesters also marched through the CBD, followed by police, disrupting traffic, banging drums and throwing signs on roads.
Police were aware a protest was planned today and unsuccessfully tried to thwart plans last week.
A driver stuck in traffic caused by the Sydney Harbour Bridge tunnel closure said she would rather the climate protesters avoided peak hour.
"I can't get to work on time, that's really annoying isn't it," she said.
Another driver said he didn't mind.
"Not much you can do about it. You've got to have a voice I suppose."
Blockade Australia organisers have warned people to expect more disruption in the coming days.
The government said it did not intend to block legitimate community rallies but had to fight against "anarchist protesters" who shut down major economic activity.
