Doctors join protest against $767m Maules Creek coalmine project

Three doctors and a medical student have been arrested after locking themselves together as part of a NSW coalmine blockade, protesters claim.

A group of 13 medical professionals and students, dubbed Medics Against Coal, spent more than four hours chained together at the Maules Creek mine site on Saturday.

Protesters oppose clearing part of the Leard state forest to make way for the new $767m mine, near Boggabri in the state's north-west.

Medical professionals from around the country joined the action to highlight the mine's health impacts but their protest was short-lived.

First-year medical intern Harry Jennens and Armidale doctor Sujata Allan, Adelaide doctor Ingo Weber and Melbourne student Lin Wang locked themselves together by putting their arms in connected pipes.

The group's spokesman, Ben Solity, said once police arrived, they voluntarily unlocked themselves as they had achieved their objective to highlight the health impacts of coal to the world.

"They were very well aware of the consequences and the potential that they would be arrested," Solity said. "They were prepared to do whatever it took to do something to stop this mine."

Solity said the four protesters were still in police custody at Narrabri. Comment has been sought from NSW police.

In a earlier statement on Saturday, Jennens said the urgent health impacts of climate change had compelled them to take action.

Medics Against Coal claim the coal mine will foul air and water around Maules Creek and spill coal dust along the railway line to Newcastle.

"The Maules Creek project is expected to operate for 30 years," Weber said in a statement. "This proposal and others like it fly in the face of current medical recommendations and must be abandoned in favour of safe alternatives."

All four were on Saturday afternoon charged with obstructing a vehicle and obstructing a driver's path, Solity said.

They are due before Narrabri local court later in May.

Two other protesters were also arrested for failing to comply with police and have been issued court attendance notices. But this hasn't deterred any of the activists.

"It's not a campaign we intend to give up on soon," Solity said. "People are not going to stop coming out here any time soon."