Seven out of ten victims of so-called online sextortion are men, according to new figures from the eSafety Commission.

Sextortion is the threat to leak sexually explicit images unless the victim meets the demands of the perpetrator.

In many cases, that's money, but it can also be demands for more nudes or to perform sex acts.

Nearly one-third of all image-based abuse reported to the eSafety Commission involves sextortion, Commissioner Julie Inman Grant told Hack.

"About 30 per cent of the reports we've got into [image-based abuse] involve some extortion or threat to share behaviour," she said.

The vast majority of victims of sextortion are men.

"Where the perpetrator's motives appear to be financial gain, the victims do tend to be male. And 85 per cent of them are over the age of 18."

But when the perpetrators' aim is to elicit sexual favours through sextortion, the victims are more likely to be underaged girls.

"About 75 per cent of those tend to be underage, and then of course in those scenarios those images constitute child sexual abuse material," Ms Inman Grant said.

"We are seeing victims of sextortion as young as 12 or 13."

Who's doing the extorting?

Veteran tech journo Stephen, who asked us not to use his surname, got an email demanding cash about six months ago.

"It was that initial reaction of, someone knows something about me. How on Earth did they do that," Stephen told Hack.

That one said 'pay me nearly $2000 in Bitcoin or else'.

Stephen writes for the Gadget Guy so he's pretty knowledgeable about the scams out there, but he said this email was different from the usual typo-ridden stuff that lands in his inbox.

They knew one of his previous passwords, and the email was well-written.

He thinks it was put out by a professional scamming syndicate.

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That seems likely in a lot of cases.

"By far the majority of these sextortion scams are perpetrated by people the victim has never met in real life," Ms Inman Grant said.

The victim can be friends online with the perpetrator for weeks or even months before the demands begin, she said.

"Usually the scenario is a male will be meeting someone who poses as female - we don't know who's behind the account - either on a social media site or a dating site," Ms Inman Grant said.

"At some point they'll ask for nude photos or go offline and do a sexy Skype."

That's when the scammers will demand cash.

"Usually it can start with hundreds of dollars, and then escalate into the thousands of dollars. It's a very lucrative scam."

What should you do if you're the victim of sextortion?

Detective Chief Inspector Mick Haddow from New South Wales Police child abuse and sex crimes squad told Hack that the key is stopping and asking yourself why someone wants your images.

"If you're communicating with someone you've only ever met in the online environment... then you need to be very careful," he said.

"People don't always tell the truth online. So you need to be more guarded, more careful, more concerned about your information or images or video you're sharing with someone."

There's certainly been a proliferation of this type of offence.

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If someone is threatening to leak your images, it's really important that you do not hand over any cash.

"Don't pay. Go to the eSafety office's image-based abuse service at esafety.gov.au," Ms Inman Grant said.

Detective Chief Inspector Haddow said the eSafety Commission will be able to tell you if a crime has been committed. They'll also be able to advice service providers like social media companies to take down any offending material.

A lot of internet scammers live outside Australia, but NSW Police said that shouldn't be seen as a barrier to getting help.

"Even if you think the offender is overseas, that's not a reason to not report it," Detective Chief Inspector Haddow said.

"Unlike almost any other crime type, this crime type is one where we do have those close international collaborations.

"This is a borderless crime in a lot of ways."