Millions of Facebook users may have noticed a big change in how they use the popular app and it is particularly affecting how they consume and react to news.

From yesterday, news publishers around the world were hit by an issue that affected their users' ability to see comments on their posts.

Newstalk ZB the New Zealand Herald and are affected, but so are all the other major news outlets.

Usually, posts would be ordered by "most relevant" and users could view previous comments before joining the conversation themselves, but now users are only seeing a blank screen.

But there is a fix.

If Facebook users choose to order the comments by "newest" then the comments will unfurl.

This provides a solution for mobile users, but desktop users may still find that they have no option to show comments.

The Herald has contacted Facebook for comment on this problem and to advise when things might return to normal.

The issue comes as Facebook and Instagram's parent company Meta posted its first revenue decline in history today, dragged by a drop in ad spending as the economy falters — and as competition from rival TikTok intensifies.

The company's stock dropped slightly in after-hours trading following the results, suggesting Wall Street was largely expecting the weak earnings report.

The results also largely followed a broader decline in the digital advertising market that is dinging rivals such as Alphabet and Snap. Google's parent company reported its slowest quarterly growth in two years on Tuesday.

Meta also faces some unique challenges, including the looming departure of its chief operating officer Sheryl Sandberg, the chief architect of the company's massive advertising business.

In addition to TikTok, the decline in ad spending during the downturn and Apple's privacy changes, "questions about Meta's leadership" — including Sandberg's exit and negative sentiment about the company as a whole — also contributed to the decline, said Raj Shah, a managing partner at digital consultancy Publicis Sapient.

- additional reporting, AP