Tens of thousands of students have taken to the streets nationwide to air their frustrations at the lack of government action in tackling climate change.

Rallies are being held across the nation on Friday after students were encouraged to use a “climate doctor’s certificate” and take a sick day from school citing global-warming concerns.

Several thousand people descended on Melbourne’s Flagstaff Gardens before marching through the city centre.

Liam Cranley said he took his children Dario, eight, and Olive, 11, out of school to attend the March because they asked him if they could go.

Cranley said their school had no qualms about his children missing class and he believed it was important to take a stand as governments at all levels needed to accelerate action on climate change.

“We’re not going to be able to live here much longer if the heat keeps going up,” daughter Olive told AAP.

A group of students from Melbourne Girls’ College attended after hearing about the rally from a teacher.

“I believe it’s worth missing half a day of school just to make sure that the next generation will actually get to live and have an education here on our planet,” year 7 student Erin said.

Hundreds of protesters converged in Sydney outside the office of Environment Minister Tanya Plibersek to chants of “shame”.

As Australia prepares for another summer of extreme heat and bushfires, the school strikers say the Albanese government is failing on its promise of climate leadership.

Min Park, 16, from Sydney, said she was striking because of Ms Plibersek’s approval of new coal and gas projects.

“She is listening to the fossil fuel lobby instead of doing her job and taking responsibility to protect the health of the planet,” she said.

“The Labor government needs to listen to young people everywhere and say no to new coal and gas projects and speed up a just transition to clean energy, because the worst impacts of climate change will be on my generation.”

Anjali Beames, 17, has been striking from school all week, studying on the steps of Parliament House in Adelaide alongside other students from the South Australian Youth Climate Alliance.

“I am studying for my future, but I am worried that without real action on climate change my future will be bleak,” she said.

Many of the marches were heavily entwined with First Nations concerns.

Torres Strait Islander law student Chelsea Aniba travelled from Saibai to Melbourne, where she joined the student protest to explain how her people were on the front line of climate change.

“It’s affecting our homes, our gardens, we can’t really grow our traditional foods like we used to anymore,” she said.

“Even our seasons are being changed.

“And of course, the main one, which is the sea levels are rising.”

Torres Strait Islander elders Pabai Pabai and Paul Kabai are in Melbourne for hearings in the landmark court case they brought against the Australian government for climate inaction and will speak at the strike.

Kabai said he was proud to stand with the young protesters to demand stronger climate action.

“The more voices we have, the stronger our fight will be,” he said.

“We are not fighting the government for ourselves – we are doing this for the Pacific, for our brothers and sisters, for our home in the Torres Strait and for all Indigenous people around the world.”

Kabai said he was happy to be supporting the school strike to help deliver a message to the government.

“I say to them, ‘help us’,” he said.

“I say to them, ‘the time for politics must stop, you must take action urgently to protect us from climate change, if you don’t, we’ll lose everything’.”

– AAP