Hilary Barry has lashed out at anti-vaxxers, saying they're like a street gang spreading propaganda online.

The Seven Sharp presenter wrote: "Vaccinate your children. That is all," on her Facebook page Thursday morning in response to a message posted on her page a few days ago.

A follower had commented that Barry was "demonising" anti-vaxxers by saying they were feral, which was unacceptable, unprofessional and insulting.

JASON DORDAY/STUFF Seven Sharp presenter Hilary Barry has hit back at anti-vaxxers, saying the anti-vax movement, from her experience, was most certainly feral.

"We still have the right to disagree; to choose to medicate or not, and to free (respectful) speech. I am against vaccination and I am NOT feral," the woman wrote.

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"I am a successful business woman and a perfectly normal caring person. Get off your high horse and show some respect and professionalism."

Barry hit back, saying the the anti-vax movement, from her experience, was "most certainly feral".

"They're like a street gang that operates on the internet trolling Facebook to spread their propaganda," Barry wrote.

"I've seen their vitriol, I've been on the end of it and so did the woman who featured in our story. So I won't apologise for something that is true."

Barry said the World Health Organisation listed anti-vaxxers as one of the top ten threats to global health, along with Ebola.

"That is an insult every anti-vaxxer should think about."