The NSPCC has warned such apps can be easily misused to send abusive messages to others or by those looking to exploit young people.
Yolo – an acronym for you only live once – has risen to the top of the free download charts on the App Store in both the UK and the US barely a week after being released.
The app was developed using Snap Kit, a piece of software by Snapchat that enables app developers to integrate their own products with the popular social network.
It allows users to post a graphic on to an image, which asks for anonymous messages that can be sent to a specific set of contacts or distributed more widely on Snapchat through its Story feature.
Those who see the request can respond via Yolo and if the original poster responds their reply is posted back to their Snapchat Story.
Many other anonymous platforms have been impacted by online abuse in the past.
Andy Burrows, the NSPCC’s associate head of child safety online said: “Apps such as Yolo that allow anonymous comments could be easily misused to send abusive or upsetting messages.
“Snapchat should justify how this app meets their duty of care to children.
“It’s essential that the Government brings in an independent regulator that will have the powers to make tech companies consider the risks that their services present for children.
“We recently issued a warning on our Net Aware site, which we created with O2, about anonymous apps as they are starting to rise in popularity again amongst children.”
Last month, the Government published a white paper on online harms, which proposes the introduction of a mandatory duty of care for technology and social media companies, who must pledge to protect their users or face punishment from a new, independent regulator.
Snapchat has not commented on the app.