TOKYO – Japanese Prime Minister Shigeru Ishiba may realize that the price of securing the support of a small opposition party and staying in power after a major electoral setback is to offer tax relief to workers part-time.

After the poor performance of the ruling coalition in the October 27 electionshe needs to find allies before next month’s vote, and the spotlight is on the People’s Democratic Party. The group, led by Yuichiro Tamaki, quadrupled its presence in parliament after campaigning for a policy to extend tax-free income benefits for part-time workers.

The DPP’s 28 votes would be the easiest path to a majority for Mr. Ishiba’s Liberal Democratic Party (LDP) and his coalition partner Komeito, who together lost 18 seats of the 233 required to pass a law.

With Japan grappling with the largest debt load in the developed world, accepting a loss of revenue in exchange for support might be the most realistic path forward.

Mr. Tamaki wants to increase the tax-free annual income limit for part-time workers from 1.03 million yen ($8,800) to 1.78 million yen. He said this would encourage part-time workers to work longer because they would not have to pay income tax until they reached a higher income threshold.

Under his proposal, employed spouses of part-time workers would also remain eligible for dependent tax breaks generally worth 380,000 yen per year, reducing the inconvenience of their partners’ overtime work.

A higher cap would help ease the country’s labor shortage while increasing household incomes, Tamaki says. On the other hand, it would reduce tax revenues for a government that keeps increasing its spending and has another supplementary budget in the works.

“This is the most important point on the DPP’s policy agenda and so there is a good chance that Ishiba will accept it,” said Koya Miyamae, an economist at SMBC Nikko Securities Inc.

Mr. Ishiba is expected to call on the DPP to form a “partial coalition,” the Yomiuri newspaper reported on October 29, citing an unidentified LDP official.

Mr. Tamaki reiterated in the morning that he was not considering forming a coalition with Mr. Ishiba’s LDP, although he was open to negotiations on political issues. He said he still intended to put his own name forward in the vote for prime minister, which the Yomiuri said is expected to take place on November 11.

“I don’t know what impact the increase in the cap will have, but it will result in a loss of tax revenue,” said Harumi Taguchi, senior economist at S&P Global Market Intelligence. “This will fuel uncertainty about how to generate revenue for necessary spending.”

Still, raising the cap could be an easier sell for the ruling coalition than changing tax rates and is perhaps the most acceptable political deal Mr Ishiba can sign to remain prime minister.

The Constitutional Democratic Party won the most seats among opposition parties with 148, but its leader, former Prime Minister Yoshihiko Noda, has ruled out a grand coalition with the LDP.

The Japan Innovation Party, with 38 seats, calls for the sales tax to be set at 8 percent across the board, the transformation of Osaka into a unified metropolitan area and increased responsibilities for the Bank of Japan , claims that represent a much heavier lift. Another obstacle to cooperation is friction between the party and Komeito.

The DPP also rejected a request for a meeting with the Constitutional Democratic Party, FNN television reported on October 29, citing an unidentified person. The CDP was considering forming a rival coalition. BLOOMBERG