Two major opposition parties in Japan have decided to contest the upcoming election together to challenge Prime Minister Sanae Takaichi’s ruling coalition. The decision was made on Thursday with the aim of attracting undecided voters ahead of a possible snap election. Takaichi, who became Japan’s first female prime minister in October, currently leads in opinion polls, and her coalition is expected to strengthen its majority in the powerful lower house of parliament.

Constitutional Democratic Party of Japan (CDPJ) leader Yoshihiko Noda announced that his party would form a new alliance with Komeito, a former partner of the ruling Liberal Democratic Party, to jointly contest the election. Noda described the alliance as a centrist alternative to Takaichi’s right-leaning coalition. Media reports suggest the election could take place as early as next month.

Officials from Takaichi’s party and its ally, the Japan Innovation Party, said the prime minister has informed them of her plan to call the vote soon after the parliamentary session begins.