Prime Minister Shinzo Abe’s ruling coalition is poised to win more than 300 of the 465 seats in the House of Representatives election on Sunday, Jiji Press forecasts.

Abe’s Liberal Democratic Party and its partner, Komeito, may take as many as 310 seats altogether, which would give the coalition the two-thirds majority needed to propose constitutional amendments.

Abe has vowed to step down if the ruling coalition fails to secure a simple majority of at least 233 seats.

The forecasts are based on reporters’ coverage of electoral districts across the country, opinion polls and past election results. A total of 1,180 candidates are running for the Lower House.

The LDP alone is likely to win close to 280 seats, compared with the 290 it held before official campaigning began on Tuesday, meaning it will remain by far the largest force in the Lower House.

In the single-seat districts, the LDP candidates are leading mainly in Hokuriku, Chugoku and Kyushu. In the proportional representation blocs, the LDP will likely come close to retaining the 68 seats it won in the previous Lower House election in December 2014.

Komeito is projected to win at least six of the nine single-seat districts it is contesting. In proportional representation, the party may fall short of retaining its 26 seats.

Tokyo Gov. Yuriko Koike’s new Kibo no To (Party of Hope) is only expected to hang on to its 57 seats, contrary to initial expectations of a big win.

Kibo no To could see all 23 of its candidates in Tokyo’s single-seat districts lose. It is also projected to win about 35 proportional representation seats — only about half the level expected to be won by the LDP.

The Constitutional Democratic Party of Japan may boost its seat count to as high as 40 from 15, including some 30 proportional representation seats. The party was recently formed by former Chief Cabinet Secretary Yukio Edano and other defectors from the Democratic Party, which was the largest opposition force.

The Japanese Communist Party is expected to see its seat count drop from 21.

Nippon Ishin no Kai, which had 14 seats before campaigning kicked off, is likely to end up nearly unchanged.

The tiny Social Democratic Party is projected to maintain its two seats, while Nihon no Kokoro o Taisetsu ni suru To (Party for Japanese Kokoro) is unlikely to win any.

New Party Daichi, a regional political party focusing on Hokkaido, may win one proportional representation seat.