Those who watch online porn are being urged to cover up their webcams in order to prevent being spied on by hackers who could record video of victims and blackmail them for cash.

Security experts at CERT and Netsafe have seen a rise in the number of reports of hackers who claim to have in their possession footage of individuals in compromising situations watching adult content and are demanding up to $500 (£390) in ransom.

How the hackers are able to get access to users' computers is by way of duping them into installing malicious software, often deployed via links on non-secure adult websites or hidden in nefarious links on phishing emails.

Once the victim visits the adult website the scammer turns on the user's webcam and records what is happening, threatening to send the footage to all their contacts.

Another variation on the scam sees criminals setting up fake online profiles on dating sites or social media using images of attractive individuals plucked from the internet. Hackers use this profile as a lure and after connecting with somebody will encourage them to perform sex acts on camera, which they then threaten to release to the public on social media.

The frequenters of porn websites are given guidance to block the webcams on their laptops with tape or use a removable cover as the first step. They are also advised to be vigilant about what they're clicking on when visiting unknown websites and only accept online invitations from people they know in real life.

A blog post by CERT says if you are unfortunate enough to find yourself caught up in a hacker's blackmail scam they stress you do not pay the ransom.

"It can be tempting to pay money to make the problem go away. In similar cases overseas, the scammers continue to ask for more money once the first ransom is paid," CERT explains.

It goes on to advise that victims should not attempt to contact the scammers. Instead, block the individual if they contacted you on social media, and even deactivate your own account.

The problem of hackers spying on users through their own webcams is something that even has the FBI worried. Former director James Comey revealed he uses tape to cover his computer cameras. Facebook CEO Mark Zuckerberg also appears to be vigilant after he was spotted in a photo with his laptop's microphone and camera covered in tape.