In a Facebook post on June 15, the Singaporean prime minister's sister, Lee Wei Ling, insisted that recent sibling rivalry within the family extends beyond a family affair, renewing allegations that the PM had misused his official power to abuse the siblings.

Lee Wei Ling, daughter of Singapore's founding father Lee Kuang Yew, and her younger brother, Lee Hsien Yang, jointly issued a stunning statement a day earlier, denouncing their older brother, Singapore PM Lee Hsien Loong, and his wife, Ho Ching, for abusing their power and exploiting their late father's legacy for personal gain - specifically, the political ambitions of their son, Li Hongyi.

The statement claimed that they have lost confidence in their brother and they no longer trust him. Blaming the PM for his departure, Lee Hsien Yang said he now feels compelled to leave the country for the foreseeable future.

Lee Hsien Loong on June 14 denied all allegations and said he was disappointed and saddened that the two siblings turned private family issues into a public affair.

Lee Hsien Yang (Photo/People's Daily)

"Ho Ching and I deny these allegations, especially the absurd claim that I have political ambitions for my son," Lee Hsien Loong responded through a statement issued by the PM's office. "While siblings may have differences, I believe that any such differences should stay in the family. Since my father's passing in March 2015, as the eldest son I have tried my best to resolve the issues among us within the family, out of respect for our parents."

Lee Wei Ling's Facebook post contradicted her brother's response, saying that if it was merely a family affair, they would not have taken it public. She made similar allegations last year, exposing the dispute within the city-state's first family to the public.

Although the accusations are vague and no evidence has been provided, it seems that at the heart of the dispute is the fate of a house in which their father lived for most of his life.

The brother-sister duo accused the PM of refusing to carry out their father's wish that the house be demolished after his death, rather than becoming a monument to him.

"Hsien Loong's political power is related to being Lee Kuan Yew's son and thus he has every incentive to preserve Lee Kuan Yew's house to inherit his credibility," the two siblings claimed in their Facebook statement.

The PM, who is currently overseas with his family, said he will consider the matter further after his return this weekend.