The Prime Minister has used a video message aimed at schoolchildren to speak against cyberbullying, labelling it "hurtful and wrong".

"I want to speak to the children of Australia, you are our future," Tony Abbott said in a video message filmed in his office.

"Everyone has a part to play in Australia and everyone belongs.

"The great thing about Australia is that we are all different, we are all unique.

"We are all special, and that is why there is no place for bullying, in the playground or on the internet.

"Bullying is hurtful and it's wrong."

The Government said 2014 research showed approximately one in five children experience bullying online, and Mr Abbott said children being bullied should not feel alone.

"If you are being bullied, I want you to know that I am behind you, that your teachers are behind you and your family is behind you as well," he said.

He has issued the video as part of a national campaign against bullying.

Today, 1,900 schools across Australia are expected to "take a stand together" as part of the 2015 National Day of Action Against Bullying and Violence.

"I encourage you to be part of that conversation," Mr Abbott said in his address.

Mr Abbott said the campaign would talk about how to stop bullying, and wished it "every success".

Yesterday, the Government appointed a children's e-safety commissioner to investigate claims of bullying against children on social media.

Former senior AFP officer Alastair MacGibbon will have the power to fine companies $17,000 a day if they do not remove offensive material when asked.

Mr McGibbon said victims of cyberbullying should first complain to the social media site, and then the commission.

"Those social media sites will voluntarily become part of the regime, but if they fail to act they'll be moved to a regulatory regime which will allow me to fine them for not acting," he told the ABC's AM program.

"What we're there for is to try and create that safety net should the rest of the system fail, and try to buttress that system and help ensure that social media sites actually do respond to the complaints that their users are making."