A leading internet security expert has said people should follow Facebook CEOMark Zuckerberg's advice and cover their web cams when not in use.

Mr Zuckerberg's laptop is visible in the background of a photo posted on Facebook on Wednesday, intended to promote Instagram reaching its latest milestone of half a billion monthly active users.

In the photo, there is a piece of tape covering the webcam and microphone port on the laptop.

The old school security device was spotted by an eagle eyed Twitter user.

BH Consulting chief executive Brian Honan, who is an information and security consultant, said Mr Zuckerberg is not being paranoid and said people should step up their web security.

“Many people in the web security business would take that precaution. We would put covers on our webcams - be it a piece of tape or a special webcam cover,” he said.

“People would cover their webcams to stop their machine being infected by malware or to stop third parties monitoring what you’re doing,” he said.

“Quite a lot of malicious software, computer viruses or malware can infect your computer and allow criminals to have complete control over your computer.”

“Not only can they monitor what you type into your keyboard but they can turn on the microphone on your computer remotely or the webcam to record what you are saying or what you’re doing,” he said.

“There have been cases where criminals have used videos or photos where they have remotely turned on people’s cameras and caught them in compromising positions or a state of undress as people may have their laptops left on in their bedrooms,” he said.

“My advice to people would be to make sure they keep their computer secure by updating software and security updates. They should also ensure they have robust and reputable anti virus software installed on their computer and have a cover on their webcam and microphone when not in use,” he said.

Pat Larkin, chief executive of Ward Solutions a leading IT security firm, said people like Mr Zuckerberg were ideal targets for hackers.

“A high net worth individual, celebrity and innovator. As he (Zuckerberg) has so much to lose, both financially and in terms of reputational damage, he needs to do all he can to reduce potential exposure to both inadvertent and malicious compromise,” he said.

“He is constantly under the spotlight, as evidenced by the amount of attention garnered by his recent apparent Twitter and Pinterest password hacks.

“People like Zuckerberg need to be online given the sector in which they operate, but they may need to do a lot more than place sticky tape across their cameras and microphones in order to be truly secure.”

Mr Larkin said all connected devices such as laptops, tablets and phones are potentially vulnerable to being compromised by a third party aiming to breach the user’s privacy.

“Proper configuration can go some length to ensuring that this does not happen,” he said.

“However, like everything in life - there are risks and rewards. If you want complete digital privacy then you are faced with a choice of using little or no digital or online services.

“The majority of consumers and organisations seem happy to operate to a level of what they believe are acceptable risks in return for the benefits that technology brings to their personal and professional life.”