Roblox is introducing new safety features for children under the age of 13, following criticism of how it protects younger users.

The free online gaming platform, which has around 70 million daily users worldwide, allows players to create their own games and play those made by others.

It is particularly popular with children – but some have complained they have been exposed to upsetting and harmful content on the site.

Starting 3 December, game creators will be asked to say whether their games are suitable for under-13s – with any that fail to do so being blocked for players 12 and younger.

And from 18 November, under-13s will also be barred from accessing “social hangouts”, which are online spaces where players can talk to each other by text and voice.

It specifies hangout experiences as games where “the primary theme or purpose” is to allow people to communicate with each other as themselves, rather than role-playing as a character.

Younger users will also be unable to use “free-form 2D user creation” from the same date, which it said were games “that allow users to draw or write in 2D and replicate those creations to other users without the completed creation going through Roblox moderation”.

It is thought that this is aimed at preventing users writing or drawing offensive images or messages which are difficult to moderate.

“We recognize the deadline is soon, but we greatly appreciate your cooperation in helping us ensure Roblox is a safe and civil place for users of all ages to come together,” it said in a post on the Roblox developer website.

According to the media regulator Ofcom, Roblox is the most popular game in the UK for children aged 8 to 12.

But it has faced criticism over its protections for younger users, with one young person telling the BBC in May he had been approached on Roblox and asked for sexual images.

At the time, Ofcom, the regulator for online safety, told tech firms to hide “toxic” content from children and published draft codes of practice.

Since then there have been further issues, with Turkey entirely blocking access to Roblox in August.

Roblox said it was making the changes to deal with “behaviour that can potentially pose a risk to our youngest users”.

“Moving forward, all creators must complete a questionnaire for each experience they want available for users under 13,” it said.

“This means that all unrated experiences will be filtered out of search and any public or recommended sorts for users under 13.”

But despite announcing the changes would begin swiftly, it said it would not begin enforcing the requirements until 2025.