The agreement comes after the ruling coalition collapsed last week, putting in peril Sanae Takaichi’s bid to become the country’s first woman premier.

Japan was in political limbo over whether the opposition bloc will unite after junior partner Komeito quit its 26-year alliance with the ruling Liberal Democratic Party (LDP).

A union would give the opposition group enough votes to name a prime minister and block Takaichi, who was elected as LDP president just over a week ago but needs lawmakers’ approval to become premier.

Kazuya Shinba, the number two of the Democratic Party for the People (DPP), told reporters that the largest opposition Constitutional Democratic Party of Japan (CDP) “asked to hold a leaders’ meeting on Wednesday”.

CDP’s counterpart Jun Azumi said they agreed, and the DPP asked them to clarify their stance on policies including national defence and use of nuclear energy, according to the Asahi Shimbun daily.

Yuichiro Tamaki the head of the DPP — the third largest opposition group in the lower house — said earlier on Tuesday that their policies diverge significantly in crucial areas.

The DPP supports nuclear energy, while the CDP, which was in power when the Fukushima nuclear accident occurred in 2011, mentions zero nuclear power in its party manifesto.

“If we were to join together in a coalition government, alignment on fundamental policies would be essential,” he told a press conference.

“If there’s no alignment, the administration will be volatile,” said Tamaki, who said last week he would be willing to stand as prime minister.

The LDP named Takaichi as its new leader earlier this month, seemingly putting her on track to rise to the premiership.

Although she could still win if opposition parties fail to agree on an alternative candidate, Komeito’s exit from the coalition due to a slush fund scandal within the LDP has sunk Japan into a new political crisis.

Takaichi, however, said at an event in Tokyo on Tuesday that she “will not give up,” according to NHK. “I’m absolutely determined to become Prime Minister,” she said.

The LDP still occupies over 40 percent of the powerful 465-seat lower house but lacks the majority it needs to name a prime minister on its own.

The CDP has said it was willing to name Tamaki or the leader of another opposition party as the premier in order to kick the LDP out of power.

Yoshihiko Noda, head of the CDP, has said that “this is a once-in-a-decade chance for a change of government”.