Mr Li Shengwu, nephew of Prime Minister Lee Hsien Loong, said in an interview published yesterday that he left Singapore because of concerns that he might be detained by the authorities in a contempt of court case.
Mr Li, son of PM Lee's brother Lee Hsien Yang, said: "In Singapore, it is possible that one can be detained and interrogated for some time without a lawyer.
"My friends had warned me that they were concerned for my safety if I remained in Singapore," he told news agency Reuters, declining to identify his friends or disclose if they had specific information.
He left Singapore on July 23 for the United States, more than a week sooner than he planned, the report said.
The Government, in its reply to the news agency's queries for its report, said that the Attorney-General's Chambers (AGC) has applied to the High Court for permission to start committal proceedings against Mr Li for contempt of court.
In the reply, PM Lee's press secretary Chang Li Lin said: "This is a well-established legal process. Clear laws and procedures apply to all cases of contempt, including this case involving Mr Li. The courts will decide on the merits of the case."
Ms Chang said the AGC has told Mr Li the proceedingswould be withdrawn if he apologised for his comments, but he has not done so.
She also said the points on detention and interrogation in the report are not accurate.
Mr Li's Facebook post on July 15 said the "Singapore government is very litigious and has a pliant court system", and foreign media had been cowed into self-censorship because of previous legal action.
The 32-year-old also shared a link to a Wall Street Journal article about the dispute between his father and aunt Lee Wei Ling on one side, and his uncle on the other, over their late father's home.
He also included a link to a 2010 New York Times editorial critical of his late grandfather, founding prime minister Lee Kuan Yew, and the Government over what the newspaper deemed as censorship of the foreign press.
Calling Mr Li's remarks "an egregious and baseless attack" on the judiciary", the AGC asked him to delete the post, and sign and publish a written apology on his Facebook page by Aug 4.
Mr Li, who is based in Massachusetts, where he is a junior fellow at Harvard University, has since amended his post, but said he will not take it down. He contends that when read in context, it was not in contempt of court.
His post came shortly after a parliamentary debate on the allegations of abuse of power his father and aunt levelled against PM Lee.
PM Lee's siblings have accused him of blocking their late father's wish to demolish the family home at 38, Oxley Road. Mr Li told Reuters his grandfather wanted the house torn down as he did not want it to feed into a cult of personality.
Ms Chang said while the late Mr Lee's personal wish was to knock the house down, he "also recognised that the Government had the right to preserve the house, and seriously considered and approved plans for the house in that eventuality". She added that PM Lee had explained this fully in Parliament.
In the interview, Mr Li also questioned if the People's Action Party (PAP) has too much control. "I worry that Singapore's ruling party tries too hard to maintain a monopoly on credibility," he said.
Ms Chang said "there is no cult of LKY", adding that it was "natural and healthy" for Singaporeans to wish to honour the memory of Mr Lee and other founding fathers.
She also said the PAP forms the democratically elected government of Singapore and anyone dissatisfied with its performance "can contest elections and try to convince voters they can do better".
"Opposition parties regularly do so," she added.