The prevalence of social media is one key difference between the current Wuhan virus outbreak and the severe acute respiratory syndrome (Sars) crisis of 2003, Prime Minister Lee Hsien Loong said yesterday.

Noting that rumours have been circulating on various channels about the novel coronavirus, he said he was very glad that the Protection from Online Falsehoods and Manipulation Act (Pofma) is in place.

"Some of it, we know, is malicious and deliberate - people who are making up stories, people who are deliberately fomenting fear, uncertainty and doubt," he told reporters during a visit to the National Centre for Infectious Diseases.

"We have acted promptly against them using Pofma, and we are very diligent in putting out information as quickly as we get it, and as quickly as we can verify it, in order to make sure that people know what is the truth - what you need to worry about and what you should ignore."

The fake news law was invoked twice yesterday in relation to the Wuhan virus.

On Thursday, a website called AB-TC City News published an article that claimed five Singaporeans had contracted the Wuhan coronavirus without going to China. The article was subsequently shared by opposition party leader and lawyer Lim Tean as well as Facebook group Say No To PAP on their Facebook pages.

Health Minister Gan Kim Yong yesterday instructed the Pofma Office to issue correction directions against AB-TC City News, Mr Lim and the Say No To PAP group.

In a statement, the Pofma Office said AB-TC City News will be required to carry a correction notice alongside its article. It noted that while Mr Lim and Say No To PAP have taken down their Facebook posts containing the falsehood, they will still have to carry a correction notice on their respective Facebook pages to ensure that people who had viewed their posts are informed of the facts.

In a separate case, Minister for Trade and Industry Chan Chun Sing yesterday instructed the Pofma Office to issue a correction direction against Mr Alex Tan and a targeted correction direction to Facebook over a post that Mr Tan made on his States Times Review Facebook page which falsely claimed that Singapore had run out of face masks.

Mr Tan, the founder and editor of States Times Review, was an opposition party member and is now an Australian citizen.

Yesterday's correction direction was the second to be issued against the States Times Review. In November last year, Home Affairs Minister K. Shanmugam issued a correction direction against Mr Tan over a Nov 23 post on the States Times Review Facebook page about People's Action Party member Rachel Ong and a Nussu-NUS Students United Facebook post.

Related Story Interactive: What we know so far about the coronavirus

Related Story Wuhan virus: Why it is still safe to attend events with large crowds

The Government also invoked the fake news law twice earlier this week to correct falsehoods about the Wuhan virus.

On Monday, SPH Magazines was asked to correct an online post on the HardwareZone forum that falsely claimed a man in Singapore had died from the Wuhan virus infection. The company, which had taken down the thread earlier in line with its community guidelines, also complied with the order.

On Tuesday, the Government invoked Pofma against Facebook to correct two posts that told people to avoid Woodlands MRT station, claiming a suspected case was discovered there. The posts, put up by different accounts, also falsely claimed the station was closed for disinfection.

The Government has also lifted temporary exemptions on general correction directions for a number of search engines and social media platforms, including Google, Baidu, Facebook and Twitter, with effect from yesterday.

A general correction direction can be issued to prescribed Internet intermediaries, telecoms and broadcast licensees, or newspapers, to get them to communicate a correction notice to all users in Singapore - not just the ones who access the falsehood - when a false statement has been conveyed and it is in the public interest to correct it.

Communications and Information Minister S. Iswaran said yesterday that as the situation continues to evolve, the information flow will be fluid. "All the more we must all rely on trusted information sources and take a firm stand against those who spread falsehoods that cause anxiety and alarm, especially at a time of heightened concern in our society," he added.