TOKYO - Japan’s prime minister said on Thursday he accepted criticism that he had not sufficiently explained why he wants a state funeral for slain former premier Shinzo Abe, but defended the decision that has helped drag his support to its lowest ever.

Prime Minister Fumio Kishida’s decision to hold the funeral on Sept 27, to be paid for by the state, has aroused widespread public opposition, largely because of revelations that ties between the ruling party and a church group could have played a part in the assassination.

“I humbly accept the criticism that my explanation was insufficient,” he told members of parliament in response to questions about the issue.

The LDP said later on Thursday it found in a survey that 179 of 379 lawmakers had some form of interaction with the church, including 17 who had received election help.

“We take these results very seriously,” Mr Toshimitsu Motegi, the party's secretary-general, told a news conference.

“From now on, we will take thorough steps within the party to make sure nobody has connections with the Unification Church.”

But a majority of voters think this will be difficult to do, multiple opinion polls have found.

Using information available on legislators’ websites and sources including videos posted by the church, Reuters found that Mr Abe and 23 members of his right-wing party faction were among those who had some kind of connection with the church.

Asked about Abe’s relations with the church, Mr Motegi said there were limits to checking facts about those who had died.

Mr Kishida has seen his support slump to its lowest levels since he took office last October as public anger over LDP ties to the church coincides with concern over surging fuel and food prices and a weakening yen. Several recent major polls have shown his backing fell below 50 per cent.

While the prime minister doesn't need to run in a national election for about three years, a further tumble in his popularity could undermine his ability to control the party and distract from policy plans such as strengthening the military - largely to counter China's more aggressive military approach to regional affairs - and reducing economic disparities.

Mr Kishida announced a state funeral for Mr Abe days after his assassination on the campaign trail in July, saying he decided as such because of his one-time mentor's contributions to the country and his achievements, recognised at home and abroad.

Polls now indicate most Japanese are against holding the event, in part because of the former prime minister's links to the Unification Church.

There has also been opposition given the cost, which the government has estimated at about 1.7 billion yen (S$16.5 million).

“Even in comparison to similar ceremonies that were held in the past, we believe the estimate is reasonable,” Mr Kishida said in response to a question on whether costs were too high.

US Vice-President Kamala Harris and Australian Prime Minister Anthony Albanese have confirmed their attendance at the ceremony, which may attract as many as 6,000 people. Local media outlets have said Canadian Prime Minister Justin Trudeau will also be there.

A representative from Taiwan will attend the state funeral, but is still discussing whom to send, the Taiwanese foreign ministry said on Thursday.

The suspect in Mr Abe's assassination cited his connections to the religious group now officially known as the Family Federation for World Peace and Unification, which he blamed for causing his family's financial ruin. The allegations triggered media investigations that revealed links with scores of other politicians, mostly from the LDP.

The party's secretary-general, Mr Toshimitsu Motegi, will say that more than 150 of its lawmakers had some form of contact with the organisation, Kyodo News said, citing LDP officials.

Known for its mass weddings and followers derisively called "Moonies" - after its founder, Sun Myung Moon - the church faced dozens of court rulings against it in Japan over its fund-raising and other practices.

The Unification Church has said it took steps more than a decade ago to curb "excessive actions" by some of its members.

Political analysts say it may be hard for Mr Kishida to regain much ground with the public in the short term given that the funeral is several weeks away.

“This issue will drag on,” said Airo Hino, a political science professor at Waseda University, noting that Mr Kishida may have waited too long to explain his decision.

“As the day for the funeral approaches and disapproval continues to grow, his support is likely to fall still further.” BLOOMBERG, REUTERS