Facebook admits analysing vulnerable youths after report leaks

Social media website Facebook is denying claims it's spying on the emotional state of young users to allow advertisers to target them.

But the social media giant admits it has done research on the subject to better understand how people express themselves.

The confidential report, leaked by The Australian, detailed how Facebook could figure out when people as young as 14 were feeling "defeated", "stressed", "useless" or a "failure", among others, by examining their posts, pictures and comments.

The tools were used to study young New Zealanders and Australians in high school and tertiary education, according to the document.

It led to accusations Facebook was helping reach users at their most vulnerable, as the company already promotes to advertisers that it can help reach people "based on their demographics, location, interests and behaviours".

But in a statement, Facebook denied the claims it had added users' emotions to the list.

"The analysis... was intended to help marketers understand how people express themselves on Facebook," it said.

"It was never used to target ads and was based on data that was anonymous and aggregated."

The company has also issued an apology and told The Australian it will be investigating the matter.