SINGAPORE - The Workers' Party cannot conclude whether the allegations made by Mr Lee Hsien Yang and Dr Lee Wei Ling are baseless or not, as their claims have not been thoroughly investigated yet, said party chief Low Thia Khiang.

"We keep our minds open, we are prepared to give the benefit of the doubt to the PM. For me personally, I will not be convinced until the entire allegation is given a convincing or conclusive airing," Mr Low (Aljunied GRC) said in Parliament on Tuesday (July 4).

He was responding to Emeritus Senior Minister Goh Chok Tong, who said Mr Low should state clearly that the allegations made by Mr Lee Hsien Yang and Dr Lee Wei Ling were baseless.

The feud between the Lee siblings erupted into the public sphere on June 14, when the duo issued a statement accusing their older brother - Prime Minister Lee Hsien Loong - of abusing his power to block the demolition of the Oxley Road family home.

Mr Goh (Marine Parade GRC) compared the current debate over the dispute to how he, as prime minister then, investigated Mr Lee Kuan Yew and then-deputy prime minister Lee Hsien Loong in 1996 over their purchase of discounted condominium units in Nassim Jade.

Back then, he found that they had acted with integrity.

Mr Low responded that he had been in Parliament back then and was convinced they were blameless, but the ongoing dispute over Oxley Road house was different.

First, the Nassim Jade case was a "market rumour", he said.

Second, the person at the centre of the Nassim Jade episode - property developer Ong Beng Seng - came forward to explain everything and clear the air.

Third, the prime minister of Singapore and the chief of the ruling People's Action Party (PAP) was not the subject of the dispute back then, said Mr Low.

"This episode, there's no investigation done, it's ownself defend ownself in a Parliament with PAP MPs," he said.

"I wonder, how would you want to convince me, my party and Singaporeans that it's conclusive and it is something we can all be convinced of entirely? Though I've said that I'm prepared to give the benefit of doubt to the PM," said Mr Low.

His position, as stated on Monday, was that the court was the correct platform to settle the dispute.

On Tuesday, Mr Low said he understood PM Lee's difficulty in suing his own siblings, but hoped the Prime Minister would clarify some doubts he had.

These included whether PM Lee had double standards in not wanting to sue his own siblings.

Mr Low pointed out that when Mr Goh was prime minister, he had sued WP politician Tang Liang Hong for making a defamatory police report in 1997.

"Does not this also show that blood is thicker than water? Own sibling cannot sue... but political opponents and critics, sue until your pants drop."

Mr Goh replied that Mr Low's remarks were "political sophistry" and added: "And as for Tang Liang Hong, he's not their brother."