Singapore’s Prime Minister Lee Hsien Loong on Monday apologised to citizens for the embarrassment the bitter public feud between him and his siblings had brought to the city state, and vowed to refute their allegations that he abused his executive power.

The premier – whose People’s Action Party (PAP) has for decades held a parliamentary supermajority – said he would grant government MPs a free vote when he gives the issue a full airing in the legislature on July 3.

Such a move is rare in Singapore. The PAP, in power since 1959, was co-founded by the three siblings’ father Lee Kuan Yew, who is credited with shaping the tiny nation into one of the world’s wealthiest and stable places within a single generation.

The three are the children of the Lion City’s revered founding leader Lee Kuan Yew. The patriarch died in March 2015 after a near five decade political career, which he held the premiership for 31 years. The two younger siblings Lee Hsien Yang, 59, and Lee Wei Ling, 62, allege that the premier abused his powers to prevent them from demolishing the family home – one of the patriarch’s final wishes he included in his final will.

The abuse of power allegations made by his two siblings have “hurt Singapore’s reputation and Singaporeans’ confidence in the government,” the premier said in a video statement that was aired on the state broadcaster Channel NewsAsia at 7.30pm.

“As your prime minister, I apologise to you for this. As the eldest of the siblings, it grieves me to think of the anguish that this would have caused our parents if they were still alive,” Lee said in the statement, in which he appeared sombre.

It was also posted on his official website and Facebook page. There was no immediate reaction to the statement by his younger siblings.

The 65-year-old premier said his ministerial statement in parliament would “refute the charges”.

“All MPs will then have the opportunity to raise questions for themselves and their constituents. I have instructed that the PAP party whip be lifted,” he said.

“I urge all MPs, including the non-PAP MPs, to examine the issues thoroughly and question me and my Cabinet colleagues vigorously. I hope that this full, public airing in parliament will dispel any doubts that have been planted and strengthen confidence in our institutions and our system of government.”

Premier Lee made his statement six days after the two younger siblings made explosive allegations against him in a six-page news release alleging how their eldest brother was abusing executive powers to force them to drop plans to demolish the family home.

Lee Hsien Yang, a former military general, and his neurologist sister Lee Wei Ling are the executors and trustees of the patriarch’s estate.

Lee Hsien Yang has said the threat he is facing from “organs of state” for taking on the premier on the matter are so grave he will leave Singapore in self-exile.

The two siblings said the premier does not want to demolish the house as he wants to preserve as parts of efforts to “milk” his father’s political capital.

Premier Lee in turn has slammed the siblings for taking a private dispute into the public domain, and said their actions had tarnished the legacy of their father.

As the saga escalated, Lee revealed he had “grave concerns” about the drafting of the seventh will – in which the so-called “demolition clause” mandating the razing of the house had appeared.

It had been removed in the previous two versions of Lee Kuan Yew’s will.

The premier called into question the role Lee Suet Fern, the wife of Lee Hsien Yang, had played in the drafting of the seventh will. The will not only reinstated the demolition clause but also returned her husband’s share to one-third of the estate.

In an earlier interview with the Post, Lee Hsien Yang said the younger two siblings’ only motivation was to honour their father’s last wish. While alive, Lee Kuan Yew publicly said he did not like the idea that strangers would be able to “trudge through” the home he lived in for seven decades.

“What could we gain from bringing this public, that would be worth political exile from our home? No personal benefit could ever balance those scales,” said Lee Hsien Yang. “We had no other way to defend ourselves and no other way to reveal the truth to the people of Singapore.”

In his statement on Monday, Lee Hsien Loong said the saga would not distract the government from “our responsibility to govern Singapore”.

“We are determined to repair the damage that has been done to Singapore,” he said.