The Japanese government's withdrawal of a controversial immigration bill reflects Prime Minister Yoshihide Suga's desire to avoid a further backlash, with his public support already hit by criticism of a sluggish COVID-19 response.

The revision to the immigration control and refugee recognition law had never been a priority for Suga, who saw it as irrelevant to the average Japanese citizen, according to his aides. Railroading it through parliament would have also enraged opposition parties and held up legislation he views as more important.

The ruling coalition of the Liberal Democratic Party and Komeito had hoped to pass the bill during the current Diet session, set to end June 16.

But the Constitutional Democratic Party of Japan and its allies demanded the government first address allegations that a Sri Lankan woman was mistreated while being held in an immigration facility before her death in March.

Liberal Democratic Party Secretary General Toshihiro Nikai (center R), Constitutional Democratic Party of Japan Secretary General Tetsuro Fukuyama (center L) and others meet in the parliament building in Tokyo on May 18, 2021. (Kyodo)

The opposition parties called for the Justice Ministry to release video footage of her detention and threatened a censure motion against the chairman of the House of Representatives' Judicial Affairs Committee.

Senior ruling coalition lawmakers met Tuesday morning and agreed to give up on the bill, with LDP Secretary General Toshihiro Nikai notifying his CDPJ counterpart Tetsuro Fukuyama of the decision around noon in a lightning-quick turn of events.

Coincidentally, exactly a year earlier Suga's predecessor and former boss Shinzo Abe was forced to retract a bill to raise the retirement age for prosecutors, amid criticism he was trying to install an ally as Japan's top legal officer.

The ordeal dealt a huge blow to Abe, the country's longest-serving prime minister, who announced his resignation in August due to a recurring intestinal illness.

Suga, chief Cabinet secretary at the time, is seen as eager to avoid a similar loss of political clout, especially ahead of elections for the Tokyo metropolitan assembly in July and the House of Representatives sometime by fall.

Public support for Suga is already down amid surging coronavirus cases and a slow vaccine rollout. His last-minute decision last week to expand a state of emergency to three more prefectures after days of health experts urging the government to do so has also called into question his decision-making.

The approval rating for Suga's Cabinet fell to 41.1 percent in a Kyodo News poll conducted last weekend, down from 44.0 percent in April.

"Abandoning the immigration bill proves the Suga administration is weakening," said a veteran CDPJ lawmaker, while a former minister of the LDP said there is "no need to risk sending public support even lower" by forcing its enactment.

The ruling coalition also has bitter memories of being routed in the 2017 election for the Tokyo metropolitan assembly after railroading controversial anti-conspiracy legislation through parliament.

A Komeito heavyweight voiced relief at avoiding a similar scenario, saying, "This time around, we should avoid showing the Japanese people any confusion."

Angering opposition parties would also jeopardize the government's proposed revision to the national referendum law, a crucial step toward realizing the LDP's long-held goal of amending the postwar Constitution.

The House of Councillors began deliberating on the referendum bill on Wednesday after the CDPJ agreed to help enact the legislation during the current Diet session in exchange for the addition of restrictions on campaign advertising and financing.

"We're finally on track to pass it. We can't just throw that chance away," said a senior Suga administration official.

Meanwhile, opposition parties said they will continue pressing the issue of the Sri Lankan woman, 33-year-old Ratnayake Liyanage Wishma Sandamali, with a senior member of the Japanese Communist Party saying she may have been subjected to "human rights violations" while being held by the Nagoya Regional Immigration Services Bureau.

But a senior CDPJ lawmaker said the quick withdrawal of the immigration bill also means the opposition no longer has leverage to pressure the government.

"The problem is how do we get them to release the video footage now?"