Of the thousands of students who walked out of class on Friday to demand federal government action on climate change, most brandished "witty", well-thought-out signage central to the group's message.

But there were a few who strayed.

Among the best of the signs, such as the one that read, "I've seen better cabinets at Ikea", were slurs and nastiness that singled out Prime Minister Scott Morrison: "F--- ScoMo", "Scum-mo is a bitch so so am I", and "I hate ScoMo more than I hate school".

Harriet O'Shea Carre, one of the originators of the School Strike 4 Climate Action from Castlemaine in central Victoria, said that these signs - though few - were contrary to the group's overall message.

"Anything towards a particular person, I don't think that accurately represents what we're trying to get across. It's not about individuals, it's about our whole group, our whole government, our whole world and how we need to change it," the 14-year-old said.

"I personally wouldn't encourage swearing because this is a peaceful strike and we don't want to be aggressive about it. We just need to get our message across."

But, she said participants weren't directed on what they could write on their signs, and the slurs could be a misguided reflection of the anger students were feeling about the lack of action on climate change.

"I think because people are just so frightened, terrified and concerned about the issue, they felt that swearing was the way to put it across," she said.

"Our message is for our government and the world to take the climate crisis seriously and start treating it like the emergency that it is so that we can have a safe future and a sustainable planet to live in."

The movement, which comes amid federal government uncertainty on energy policy, has attracted mass controversy over the past few days, with many in Canberra taking aim at the students who took part.

Mr Morrison said in question time in Parliament on Monday that Australia should have "more learning" and "less activism" in schools, while the federal Minister for Resources Matt Canavan told 2GB that protesting only taught students "how to join the dole queue".

Attempts were made to contact Mr Canavan for this story, but the Herald received no response.

The response from the public, though, has been mostly positive, with participants being applauded for bringing climate change to the forefront of the national conversation.

"I've had a lot of people come up to me and just congratulate me. We're finally seeing some action happening," said 17-year-old Castlemaine Secondary College student Charlie Bell Willcock.

As for what's next for the strikers, they intend to meet via Skype on Monday night to discuss further protests on climate change, with an emphasis on issues such as the approval of the Adani coal mine.

"I think our next things will probably be focused on coal mining but we'll be playing it as we go to see how people respond and what needs changing and improvement," Ms O'Shea Carre said.

The Strike 4 Climate Action movement has been inspired by a 15-year-old Swedish student, Greta Thunberg, who started boycotting classes before parliamentary elections in her nation on September 9, and continues to skip school every Friday.

ACT Minister for Climate Change Shane Rattenbury said last week, “Young people don’t want to just stand by and watch this climate emergency roll out.

“As future leaders, they’re making their voices heard - and the message is clear.”

With Peter Hannam and Dan Jervis-Bardy