News publishers are facing an uphill task as social media has become a dominant news source, changing the way news is packaged and distributed.

A report by the Reuters Institute for the Study of Journalism (RISJ) has found that over half of online users obtain news from Facebook and other social media platforms.

The trend is expected to pose a challenge for publishers of quality news as it hits their revenue, with users declining to pay for news and using ad-blockers.

Although the distribution of free news through social media platforms allows publishers to gain more readers, it also poses challenges for them to become a known source of news, the RISJ said in its annual Digital News Report.

Reuters Institute director of research Rasmus Kleis Nielsen said: "Clearly, the era in which news was a fairly stable product, published or broadcast in a single fixed form which people could pay attention to or not is gradually coming to an end."

For the first time in the study, 28% of the 18-to-24-year-olds surveyed said that social media is their leading source of news, overtaking 24% who cited television.

Reuters Institute research associate Nic Newman said: "The growth of news accessed and increasingly consumed via social networks, portals and mobile apps means that the originating news brand gets clearly noticed less than half the time in the UK, and Canada.

"In countries like Japan and South Korea, where aggregated and distributed news is already more widespread, the brand only gets noticed around a quarter of the time when accessed through news portals."

According to the study, Facebook is the most common social media outlet for news, with 44% of the surveyed participants using it to watch, share and comment on news.

YouTube occupied the second place with 19%, followed by Twitter with 10%.

While a majority of those surveyed using a smartphone to access news, Sweden recorded the highest levels of device usage for news at 69%, followed by Korea and Switzerland at 66% and 61%, respectively.

The survey found 36% wanted algorithms to select news for them, compared to 30% who preferred editors or journalists.

Newman said: "We find strong concerns that personalised news and more algorithmic selection of news will mean missing out on important information or challenging viewpoints. Having said that, we find that young people are more comfortable with algorithms than with editors."