Prime Minister Lee Hsien Loong is suing Roy Ngerng for defamation for alleging that Mr Lee criminally misappropriated Central Provident Fund (CPF) savings.
It is the first case in Singapore of a blogger being taken to court by a political leader over online defamatory comments.
The legal papers were filed in the High Court yesterday and served on Mr Ngerng's lawyer, M. Ravi, who confirmed he had received them.
Mr Lee's lawyer, Senior Counsel Davinder Singh, also sent Mr Ravi a separate letter yesterday that responded to his point about Mr Ngerng's constitutional right to continue writing on the CPF.
Mr Singh said that PM Lee "has never once said" the 33-year-old health-care worker is to remove his blog posts, including those on the CPF, other than those specifically identified in Mr Lee's legal letters.
Mr Ngerng knows this, Mr Singh added.
Despite that, Mr Ngerng has "sought to give the false impression that our client is seeking to prevent him from expressing his views on the CPF or from exercising his constitutional rights", said the Senior Counsel.
"That disingenuous suggestion was made in a letter which your client intended to make public, to bolster his standing and in aid of his continuing public campaign against our client," wrote Mr Singh.
Calling it "malicious conduct'', he said Mr Lee will ask the court to consider it when assessing aggravated damages.
Mr Lee is claiming damages, an injunction to stop Mr Ngerng from further defaming him, and costs.
This article by The Straits Times was published in MyPaper, a free, bilingual newspaper published by Singapore Press Holdings.
Get a copy of The Straits Times or go to straitstimes.com for more stories.