Hoang Quan, an office clerk in Da Nang’s Thanh Khe District, says ads with scantily dressed women and gambling games often appear when he surfs the message board or watches Reels on Facebook.

“The ads are suggested by Facebook and displayed at specific times: After 4 p.m. it is gambling; in the evening it is sexy and suggestive content,” he said.

Tuan Phuong of Ho Chi Minh City, another Facebook user, sees similar ads pop up constantly.

“Toxic content appears next to posts. Every time I scroll through a few posts of my friends, the News Feed inserts a gambling ad,” he says.

He says he is flustered when he sees Facebook livestreams with inappropriate content when he is sitting with his child in the evenings.

In a VnExpress survey this month 96% of participants said they had seen gambling and other offensive ads on Facebook, with 81% saying they are frequent.

An ad with an offensive image on Facebook. Photo by VnExpress/Khuong Nha

The situation seems to have worsened in March, with members on some technology forums suggesting Facebook’s censorship filter could be faulty.

The contentious ads are usually in the form of a livestream and direct users to gambling websites. As soon as the livestream ends the video is removed from the platform by Facebook fanpages, leaving no trace.

According to online marketing expert Mai Thanh Phu, the Facebook censorship system only looks at the beginning of a livestream and not the whole of it.

“In the beginning the livestream will not have any objectionable content. After Facebook approves the livestream and starts charging for the advertising, the fanpage will become a gambling ad.”

He says buying a fanpage to livestream or Facebook ads is simple and costs just a few million dong (VND23,600=US$1).

Users can turn them off and report violations though there is no guarantee the same content will not appear again, he warns.

A gambling ad suggested to Facebook users on a mobile phone. Photo by VnExpress/Khuong Nha

The Facebook representative in Vietnam has not commented on the above issue.

According to Ha Hai of the Ho Chi Minh City Bar Association, it is illegal for Facebook to allow gambling ads according under the Law on Advertising.

“Facebook must actively control, block and remove [illegal content], and not wait for users to report or authorities’ instructions.”

In the past Facebook users have reported seeing ads for cannabis seeds and poppy though Vietnam has stringent drug laws.

Last November Minister of Information and Communications Nguyen Manh Hung said the ministry plans to start inspecting advertising on cross-border platforms.