Addressing hundreds of people at the student climate strike in Ballarat, organiser and high school student Ellie Fenton was calm but furious in her denunciation of climate change inaction.

The second rally in Ballarat was one of more than 3000 held around the world on Friday, with students going on strike to draw attention to pressing concerns about climate change.

Led by high school students from across the district, there were seven-year-olds holding signs they'd made with their parents, and more adults marching alongside them to show their support.

In Ballarat, there were more people than the previous rally in November last year and a broader range of ages.

Another organiser, Rosa Varga-Miller, defended the students leaving school to protest.

"We learn better as a community talking about it outside of school," she said.

"What's the point of going to school if the planet's going to die in a couple of years?"

Mount Blowhard Primary School had an enthusiastic contingent at the rally.

"We're protesting to stop using coal power and save the world," said 10-year-old William Bray.

"Some of the animals, the polar bears, are dying because the sea levels are rising and the ice is melting," 10-year-old Liana Raufer added.

While there had been rumours that schools would take action if students walked out for the rally, representatives from most of the region's high schools were spotted.

"We're here to support the action against climate change, because we need more people to come together - if there's more people then we can make a bigger difference," Daylesford College student Alice Dennis said.

"We heard about it on the news and decided it was something we wanted to support."

Neve Robinson, also from Daylesford, said they had peers attending the massive Melbourne rally but they wanted to support the local protest.

"We wanted to be more local, and support the locals," she said.

Another organiser, Alex Drew, said it was important for there to be rallies in regional areas, as well as in the cities.

"Rural people are highly affected by this, and I think rural politics is something that should be acknowledged in this debate," he said.

"With rising temperatures for farmers, and droughts, it affects people around Ballarat and in rural areas extensively."

Joining the students were parents and grandparents. A mother who attended, Lindy Churches, said she was impressed at the turn-out.

"It's very necessary, it's great to see them caring about it and leading the charge," she said. "If they can skip school to go to a sports day or any other excursion, I don't see why this is any different."

Gail Weston said she was acting now to protect her grandchildren.

"I think we have a responsibility, being one of the generations that have contributed so immensely to the problem," she said. "It's nice to see this emerging generation with so much passion and commitment to a cause."