The students, who have been involved in the School Strike for Climate, are being supported by Sister Brigid Arthur, an 85-year-old Catholic nun connected to the Brigidine Asylum Seekers Project.

The teenagers, aged between 13 and 17 years from four different states, on Tuesday filed an application in the Federal Court to prevent Environment Minister Sussan Ley giving final approval to the Vickery coal mine extension project in northwest NSW.

The class action, prepared by Victorian firm Equity Generation Lawyers, seeks to invoke the minister's common law duty of care to protect younger people against climate change.

The first applicant Anjali Sharma, 16, from Melbourne, says Australia is facing increasing risk from fires, floods and storms.

"Every consecutive summer is labelled 'the worst summer this country has ever faced', and yet instead of addressing this crisis more mines are being given the green light," she said in a statement on Wednesday.

"This has to stop and I am proud to be doing something to help stop it."

Laura Kirwan, 16, from Sydney, said the climate crisis would disproportionately impact young people.

"The government has a duty to young people to protect our futures from the impacts of climate change, including stopping the climate impacts of the Vickery Extension Project," she said.

Lawyer David Barnden said the matter was lodged on Tuesday and the minister has accepted service.

The Vickery extension project is a proposal to construct an open-cut coal mine and associated on-site infrastructure about 25km north of Gunnedah.

Vickery, which is owned by Whitehaven Coal, was approved by the Independent Planning Commission NSW last month but still requires the federal minister's final approval.

A spokesman for Ms Ley confirmed she has received a copy of the application but would not provide further comment as the matter was before the court.

Australian Associated Press