Barnaby Joyce has called for a major crackdown on social media misinformation after “completely and utterly fictitious” rumours about his family spread online.

The Deputy Prime Minister slammed posts suggesting former NSW Nationals leader John Barilaro’s abrupt retirement from politics was because he was in a relationship with one of Mr Joyce’s daughters.

“It’s total and utter rubbish,” Mr Joyce told ABC radio on Thursday.

He said it was essential more was done to force social media companies like Facebook and Twitter to stop people from spreading lies.

“From my own personal experience of recent times, you have got to get to a point where you say enough is enough,” the federal Nationals leader said.

“These platforms just say ‘oh well it’s too hard to control’.

“It’s not too hard for you to collect your billions of dollars from it and apparently it’s not too hard for you set up vessels to avoid tax in Australia.”

Prime Minister Scott Morrison backed up his deputy later on Thursday, saying social media platforms had become a “coward’s palace” for their lack of accountability in enabling hate speech and bullying.

“People can go on there, not say who they are, destroy people’s lives, and say the most foul and offensive things to people, and do so with impunity,” Mr Morrison said.

Scott Morrison had strong words for social media platforms and its users. Photo: AAP

“Now that’s not a free country where that happens. That’s not right. They should have to identify who they are.

“The companies, if they’re not going to say who they are, well, they’re not a platform any more, they’re a publisher. They’re a publisher.”

The PM said Australia was a world leader in tackling social media platforms.

“We intend to set the pace. We value our free society. And in a free society, you can’t be a coward and attack people and expect not to be held accountable for it,” he said.

Mr Joyce said he would speak to US politicians who are conducting a congressional inquiry that unearthed explosive allegations against Facebook.

Frances Haugen – a former Facebook data scientist – told a hearing the company was dishonest about efforts to counter misinformation and knew Instagram could have a toxic effect on young girls.

Mr Joyce said billions of dollars were being spent on mental health that could be seriously damaged through social media.

“One of the greatest mechanisms of the destruction of people’s mental health is sitting on the kitchen table or in the corner of the room,” he said.

“If you go to any school and talk to any parent, this is one of the greatest fears – the destruction of their children by innuendo, by slurs.”

He said it wasn’t just about his daughter’s experience but a broader problem across society.

“The idea that someone can have this sort of pseudonym on Twitter and say the most outrageous things, and we in 2021 just sit back and say ‘that’s fair enough’ – that’s got to stop,” Mr Joyce said.

Facebook chief Mark Zuckerberg has described Ms Haugen’s testimony as false and insists the company cares deeply about safety.

Communications Minister Paul Fletcher on Wednesday said the “special treatment” online companies had gotten away with was no longer acceptable to the community or government.

Mr Fletcher did not rule out laws to crack down on Facebook or other social media over misinformation.

-with AAP