A rap video by a local YouTuber in response to a recent "brownface" advertisement "crosses the line" and is not acceptable, said Home Affairs and Law Minister K. Shanmugam.

"This rap video insults Chinese Singaporeans, uses four-letter words on Chinese Singaporeans, vulgar gestures, pointing of middle finger, to make minorities angry with Chinese Singaporeans," he said of the video featuring YouTuber Preeti Nair and her brother, rapper Subhas Nair.

"When you use four-letter words, vulgar language, attack another race, put it out in public, we have to draw the line and say 'not acceptable'," he told reporters yesterday.

Noting that he takes a "zero tolerance" approach to such matters, Mr Shanmugam said if "speech, songs like this are allowed, slowly but surely, it will get worse".

The minister said he has asked the police to investigate the matter.

In a statement last night, the Infocomm Media Development Authority (IMDA) said it issued a notice to the video's publishers to take down the clip, and they have complied.

IMDA said it assessed that the video is prohibited content under the Internet Code of Practice, and objectionable on grounds of public interest and national harmony.

The 2 min 50 sec video was taken down from Facebook and other social media platforms yesterday afternoon. Ms Nair, who is also known as Preetipls, and her brother could not be reached for comment.

The video was uploaded on Monday in response to a recent ad by e-payments website epaysg.com featuring Mediacorp actor and DJ Dennis Chew. Mr Chew portrayed characters such as a woman in a tudung and a man with visibly darker skin.

Broadcaster Mediacorp later apologised for the controversial ad and the epaysg.com website has also removed it.

Yesterday, Mr Shanmugam said it is "not a defence" to say that the rap video had been put up in response to the ad. "If (it was) something you didn't like, then you ask for an apology. If you think it is criminal, you make a police report. You don't cross the line yourself."

He said people may ask why the Government is taking this so seriously - that one video is not going to lead to violence, and people will laugh this off. This may be the case, but if this one rap video is allowed, then hundreds of others have to be allowed too, Mr Shanmugam said.

"What do you think will happen to our racial harmony? Social fabric? How will people look at each other?" he asked.

"And suppose you allow this video? Let's say a Chinese now does a video attacking Indians, Malays using four-letter words, vulgar gestures... And let's say there are hundreds or thousands of such videos. How do you think the Indians and Malays will feel?

"Would people feel safe? Will the minorities feel safe? There are good reasons why Singapore is different, why there is racial harmony here, why all races feel safe, why minorities feel safe. And we must maintain that," he added. Similarly, if vulgarities were used to describe another person's religion, this will also not be allowed, he said.

On the epaysg.com ad, the minister noted that 30 years ago, people would have said it was in "poor taste" and "passe". Today, it will be met with a lot of distaste, he said.

Other politicians also weighed in on the incident yesterday, criticising both the ad and the rap video, while stressing the importance of maintaining racial harmony.

Senior Minister of State for Communications and Information and Transport Janil Puthucheary said he found both the ad and video unacceptable, adding that "two wrongs don't make a right".

Mr Shanmugam also said he had asked lawyers to look into the epaysg.com ad, and their view was that it is not an offence.

Institute of Policy Studies senior research fellow Mathew Mathews said some people, including millennials and Ms Nair's fans, may be upset by the Government's tough approach towards the video.

Going by the comments on the video before it was taken down, people do not seem to be offended and are aware that it is targeted at those who are racist, he said.

"But for an audience which does not know all the context, may not be a fan, and doesn't understand all your good intentions, they could see it as being very insulting," Dr Mathews added.

The video also talks about the entire Chinese community, rather than just being a critical commentary of those responsible for the "brownface" ad, he said.

"The video is a racist way of addressing racism, which I think is done in very poor taste."