Thousands of Australian students have defied calls by the Prime Minister to stay in school and instead marched on the nation's capital cities, and some regional centres, demanding an end to political inertia on climate change.

Key points: Students called for politicians to act on climate change warnings

Students called for politicians to act on climate change warnings Thousands of young people were inspired by 15-year-old Swedish pupil Greta Thunberg's protest in Stockholm

Thousands of young people were inspired by 15-year-old Swedish pupil Greta Thunberg's protest in Stockholm Resources Minister Matt Canavan criticised demonstrators for missing out on school

Protests were held in Melbourne, Sydney, Brisbane, Perth, Coffs Harbour, Bendigo and other cities, as students banded together to pressure the Morrison Government in the lead-up to a federal election.

"The politicians aren't listening to us when we try to ask nicely for what we want and for what we need," said Castlemaine student Harriet O'Shea Carre.

"So now we have to go to extreme lengths and miss out on school."

It follows similar protests in Canberra and Hobart earlier this week, which have spurred on the junior activists.

Students in Sydney used wordplay to make their point. ( ABC Radio Sydney: Harriet Tatham )

Climate change protesters in Melbourne took aim at Scott Morrison. ( ABC News: Andie Noonan )

Students in Sydney used song lyrics to draw attention to climate change. ( ABC Radio Sydney: Harriet Tatham )

The groundswell was inspired by 15-year-old Swedish student Greta Thunberg, who pledged to protest outside parliament in Stockholm until the country caught up on its commitments under the Paris Agreement.

News of her one-woman vigil caught the attention of Harriet O'Shea Carre and Milou Albrecht, both 14.

The pair, from the Castlemaine Steiner School, and a group of other climate-concerned teens travelled to the nearby regional city of Bendigo, about 90 minutes from Melbourne, to hold their own protest outside the office of Nationals senator Bridget McKenzie.

That in turn sparked Friday's protests across the nation.

"We have to sacrifice our education, which is something we really value, so we're showing them that at the moment this is even more important than our education," Harriet O'Shea Carre said.

Young Queenslanders gathered at Parliament House in Brisbane. ( ABC News: Lucy Murray )

Students in Melbourne said they had been forced to protest to be taken seriously. ( ABC News: Andie Noonan )

Students in Melbourne gathered on the steps of Parliament House. ( ABC News: Andie Noonan )

"We have tried so many other ways, we've tried just asking, we've tried telling them, and so we really just need to show them now so we're just going to keep pushing and keep trying because we love the natural world."

'You don't learn anything from protesting'

But the protests have sparked their own reaction among key members of the Federal Government who have used commercial radio to dress down the students.

Resources Minister Matt Canavan said the only thing children would be learn from the protest was how to collect government benefits.

"Walking off school and protesting, you don't learn anything from that," he told Sydney radio station 2GB.

"The best thing you learn about going to a protest is how to join the dole queue.

"That's what your future life will look like, up in a line asking for a handout, not actually taking charge of your life and getting a real job."

Puns were used by many students trying to make a point at the Melbourne protest. ( ABC News: Andie Noonan )

Mr Canavan said he instead supported children learning science.

"I want kids to be at school to learn about how you build a mine, how you do geology, how you drill for oil and gas, which is one of the most remarkable scientific exploits of anywhere in the world that we do," he said.

"These are the type of things excite young children."

But Mr Canavan's comments have been roundly rejected by one parent, Trent, who was at the protest with his eight-year-old child and their friends.

"They've actually been looking at climate change at school and they have a pretty incredible understanding of the science," he told ABC Radio Melbourne.

"I think what's striking in Matt Canavan's comments is how demeaning he is about young people and what they actually know, and how he underestimates their understanding," he said.

"I heard students today at the rally talking about the IPCC report, talking about the 700 odd days until emissions can peak before we exceed 1.5 degrees.

"These are kids that actually understand the science in a way that I think most of parliamentarians don't."

Earlier this week Prime Minister Scott Morrison revealed he was also not impressed with students taking time off to protest.

"We don't support the idea of kids not going to school to participate in things that can be dealt with outside of school," he said.

"We don't support our schools being turned into parliaments. What we want is more learning in schools and less activism in schools."

Friday's protests in Australia's biggest cities follow similar events in Canberra and Hobart. ( ABC News: Andie Noonan )

'If you were doing your job properly, we wouldn't be here'

In Adelaide, about 300 students rallied at South Australia's Parliament House, forcing police to block off a lane of traffic on North Terrace as another 200 onlookers spilled onto the road.

Organiser Deanna Athanosos, who is in year 10, said Mr Morrison's rhetoric towards the strike made her laugh.

"If you were doing your job properly, we wouldn't be here," she said.

Zel Whiting was among hundreds of South Australian students protesting on Friday. ( ABC Radio Adelaide: Malcolm Sutton )

Students in Adelaide were furious about the Prime Minister's rhetoric on striking. ( ABC Radio Adelaide: Malcolm Sutton )

Year eight student Zel Whiting also took aim at the Prime Minister.

He said he was increasingly frustrated with the Government and its "lack of awareness or activity on climate change and its dangers".

"Mr Morrison says schools are not parliament," he said.

"Mr Morrison, take a seat. You are about to be schooled.

"If everybody can contribute minor things that help the environment, such as using less plastics and not leaving your lights on — very small things — if everybody in Australia did that, we could really make a difference," he said.

Charlie, who's in grade 3 and from Sydney, was at Friday's climate protest in Adelaide. ( ABC Radio Adelaide: Malcolm Sutton )