Child safety campaigners today warned that WhatsApp's 'disappearing messages' feature could provide a 'cloak of invisibility' for paedophiles.
The Facebook-owned service will soon allow users to set the app to automatically delete their messages a week after being sent.
WhatsApp said the long-rumoured update, similar to one used by Snapchat, was designed to give users the option to keep conversations 'lighter and more private'.
But the NSPCC today slammed the new feature, warning that it would help groomers 'avoid detection and erase evidence'.
Andy Burrows, Head of Child Safety Policy at the NSPCC, told MailOnline: 'Despite its age restriction many under-16s use WhatsApp, and Disappearing Messages could put children at greater risk of harm by providing groomers with yet another tool to avoid detection and erase evidence.
'Facebook must spell out how they mitigated the effects this feature will have on their, and law enforcement's ability to combat grooming and child abuse images when efforts are already hampered by the impact encryption has on WhatsApp.'
Child safety campaigners today warned that WhatsApp's 'disappearing messages' feature will provide a 'cloak of invisibility' for paedophiles
But the NSPCC today slammed WhatsApp's new 'vanishing messages' feature, warning that it would help groomers 'avoid detection and erase evidence'
He added that the upcoming Online Harms Bill should compel social media platforms to 'consider the implications new features will have on their young users'.
'It is crucial that new laws are clear that failure to protect children from avoidable harm will result in substantial financial and criminal sanctions for tech firms and named managers,' Mr Burrows said.
John Carr OBE, a former government adviser on online child safety, told the Daily Telegraph: 'A cloak of invisibility is just what paedophiles want. This is another gift and helping hand to them from big tech, which further imperils children online.'
A spokesperson for WhatsApp told MailOnline the messaging service was built to 'enable people to report problematic content to us'.
The company previously said that either user can activate the feature for themselves, while in group conversations the admin user will have control.
'We're starting with seven days because we think it offers peace of mind that conversations aren't permanent,' a WhatsApp spokesperson said.
Andy Burrows, Head of Child Safety Policy at the NSPCC, told MailOnline the Online Harms Bill should compel Facebook to 'consider the implications new features will have on young users'
The Facebook-owned service previously said that either user can activate the feature for themselves, while in group conversations the admin user will have control
HOW TO TURN DISAPPEARING MESSAGES ON OR OFF IN WHATSAPP
You can send messages that disappear on WhatsApp by turning disappearing messages on, or removing them by turning them off.
Once disappearing messages have been enabled, new messages sent in the chat will disappear after seven days.
The most recent selection controls all messages in the chat. Messages sent or received before disappearing messages is enabled won't be affected.
Either user can enable disappearing messages in an individual chat.
To enable disappearing messages:Open the WhatsApp chat. Tap the contact's name. Tap Disappearing messages. If prompted, tap CONTINUE. Select On.
To disable disappearing messages:Open the WhatsApp chat.Tap the contact's name.Tap Disappearing Messages.If prompted, tap Continue.Select Off.
This can be done 'while remaining practical so you don't forget what you were chatting about,' they added.
'The shopping list or store address you received a few days ago will be there while you need it, and then disappear after you don't.'
Facebook confirmed that unopened messages will also disappear after seven days.
However, previews of messages - even ones that have been deleted in the app - may still be displayed in a user's notifications until WhatsApp is opened.
The firm added that quoted text used for replies will remain visible even after the original message has disappeared.
There is also nothing in place to stop the other user from screenshotting a message, and unlike Snapchat, WhatsApp won't warn you if they do take a screenshot.
'Only use disappearing messages with trusted individuals,' the company wrote on a blog post, adding that someone could also photograph the message with another device or copy and paste the text before it disappears.
By default, media you receive in WhatsApp will be automatically downloaded to your photos app on your mobile device, the firm confirmed.
If disappearing messages are turned on, media sent in the chat will disappear, but will be saved on the phone if auto-download is on.
The new feature will be rolled out to users this month, WhatsApp said, adding it will work for iOS and Android users around the world.
To enable to the feature you just go into the chat you want to use it in, tap a contact name, tap disappearing messages, say continue and then on.
Either user can enable or disable the feature and to turn it off just do the same but in selecting off instead of on.
It comes after another revamp to the app earlier this week, when WhatsApp announced a new storage management tool would enable users to mass delete gifs, videos and images from chats which are taking up space on their phone.