The protests organised by Blockade Australia are in their 10th consecutive day and continuing despite threats of hefty jail sentences.

Blockade Australia says two more activists entered the world's largest coal port on Wednesday night, with one locking themselves to a piece of coal moving equipment while another abseiled from machinery.

The organisation says the protesters have forced the port to cease operations for the night and it's their 15th action at the site since protests began on November 8.

NSW Environment Minister Matt Kean says the protests are "completely out of line" and wants police to "throw the book at them", he told 2GB radio Sydney on Wednesday morning.

Another two protesters on Tuesday night entered the port and attached themselves to a key piece of machinery that loads and unloads coal, shutting down the port.

"Pull your heads in - get out of the way and stop hurting other people going about their lives, running their businesses," Mr Kean told Sydney radio 2GB on Wednesday.

"There are hundreds of ways to make your views known and advocate for change but risking the lives of rail workers is definitely not one of them."

Blockade Australia said the activists, named only as Zianna and Hannah, climbed to the top of machinery and suspended themselves out of reach.

"As dawn broke on the coal port the sound of machinery was interrupted as the two protesters used an intricate set up of ropes to manoeuvre themselves over the edge," the activist group said in a statement.

Protests have disrupted the port and surrounding rail infrastructure in the past two weeks, prompting police to establish a strike force to crack down on the high-profile stunts.

NSW Police Commissioner Mick Fuller said the activists risked charges with potential jail sentences of up to 25 years after some locked themselves onto trains and tracks around the port to stop coal trains.

The NSW Crimes Act says a person is liable to be charged if they interfere with a railway or locomotive with the intention of endangering a person's safety.

Acts with the intention of causing a derailment can result in sentences up to 14 years.

Protester Zianna said she wanted "to challenge the ruling order of domination and exploitation that is buckling our life support systems".

"It is now our duty to defend the biosphere that gives us life and to every person that Australia has forgotten and ignored," she said.

Australian Associated Press