A rare and unexpected family feud has been played out in public between Singapore’s prime minister and his sister over the anniversary of the death of their father, Lee Kuan Yew.

In a Facebook post on Sunday, neurosurgeon Dr Lee Wei Ling said the government was trying to use the first anniversary of the death of Lee Kuan Yew, Singapore’s founding father, to “hero worship” him, according to Channel NewsAsia, a government-owned television news agency.

It said Lee Wei Ling had suggested that her brother, the Singaporean prime minister, Lee Hsien Loong, was “abusing his power” by conducting elaborate anniversary events and trying to establish a political dynasty.

Channel NewsAsia said the post had been taken down later on Sunday. However, a few hours later, Lee Hsien Loong wrote on Facebook that he was “deeply saddened” by the accusations, calling them “completely untrue”.

“The idea that I should wish to establish a dynasty makes even less sense. Meritocracy is a fundamental value of our society, and neither I, the PAP [People’s Action party], nor the Singapore public would tolerate any such attempt,” he said.

The PAP has been a solidly united political entity since it was formed by Lee Kuan Yew in 1954. It has won a majority in every election since 1959.

Lee Kuan Yew was prime minister from 1959 to 1990 and remained an influential figure in the government for several years after he stepped down. With Lee Kuan Yew having previously sued critics for defamation for alleging nepotism in his government, such an accusation apparently coming from within his family is a political bombshell.

He died on 23 March 2015 and the government has been carrying out a host of public events this year to commemorate his death.

“The first anniversary of a person’s passing is a significant moment to remember him and reflect on what he meant to us. The more so with Mr Lee Kuan Yew,” Lee Hsien Loong said in his Facebook post. He added that his government recognised the “strong desire” of many in Singapore to show their respect for Lee Kuan Yew and said the events and observances were “generally appropriate”.

Channel NewsAsia said that in her Facebook post, Lee Wei Ling had reproduced her correspondence with the editors of The Straits Times over the draft of an opinion piece that she had written on the anniversary programme. The piece was not published by The Straits Times and it was eventually posted in full on her Facebook page, Channel NewsAsia said.

In one of the emails released by Lee Wei Ling, the agency reported, she said that she and Lee Hsien Loong “are at odds on a matter of principle” with regard to the commemoration and that the prime minister had “no qualms [about] abusing his power to [have] a commemoration just one year after Lee Kuan Yew died”.