People protesting on railways near the world's largest coal port north of Sydney are being threatened with potential jail sentences of up to 25 years.
NSW Police on Tuesday announced a strike force to crack down on demonstrators who have been targeting the Port of Newcastle.
Commissioner Mick Fuller says people "are coming from other states and territories with particular expertise and they're locking themselves onto these locomotives and tracks".
Protesters from Blockade Australia have repeatedly disrupted operations around the port during the past week.
Two protesters on Tuesday night entered the port again and attached themselves to a key piece of machinery that loads and unloads coal, shutting down the whole port.
"Australia is pushing life towards extinction. It's life or death at this point," one of the protesters, a 24-year-old gardener, said.
Police have arrested 19 protesters so far, with NSW Police Minister David Elliott saying officers are "not mucking around anymore".
The protests are "nothing short of economic vandalism", he said.
"Police are taking a zero-tolerance approach to those that want to infiltrate our rail network," Mr Elliott said.
Among those arrested are two Victorian women, aged 24 and 28, who have been charged with doing an act with intent to kill or injure person on railway.
Mr Fuller said the pair, who "walked out of court laughing", would face the charges that carry a maximum 25-year sentence.
The NSW Crimes Act says a person is liable to be charged with the offence if they interfere with a railway or locomotive with the intention endangering a person's safety.
Acts with the intention of causing a derailment can result in sentences up to 14 years.
"These matters will hopefully hold up in court," Mr Fuller told Sydney radio 2GB on Tuesday.
But a Blockade Australia spokesperson said the women did not cause physical harm to anyone, calling the threat a "draconian overreach of police power".
The organisation says the two women have been hit with "trumped up charges designed to intimidate those engaging in non-violent direct action".
It said it would continue to take sustained and disruptive action for as long as necessary.
However, NSW Police Assistant Commissioner Peter McKenna defended the "strong approach, saying the attempt to secure a 25-year penalty is "commensurate with the level of danger and criminality we are now seeing... they're entering rail corridors with moving trains, not just coal trains".
Deputy Premier Paul Toole says the protest actions are an "absolute kick in the guts" for farming and mining communities.
"You have a right to protest, but if you think by putting a car on the rail network is a way of protesting safely you've got a real shock coming your way," Mr Toole said.
Opposition police spokesman Walt Secord supported the creation of a taskforce he said targeted "idiots".
"I support the right to lawful protest, but I don't support risking the safety of workers or threatening jobs and the economy," Mr Secord said.