TOKYO (BBC) -- Polls have opened in Japan in national elections for the country's upper house of parliament that could see Prime Minister Shinzo Abe forced from office. This is the first electoral test for Mr. Abe since he took office in September.

Although the election will not directly affect Mr. Abe, correspondents say a heavy defeat for his Liberal Democratic Party (LDP) could force him to resign. His popularity has been hit by a series of ministerial gaffes and scandals, and opinion polls suggest a poor result. If the citizens let Abe continue his governance, this country will never see democracy again The most significant factor has been a nationwide pensions debacle, with a government agency admitting it has lost records relating to millions of payments. Pensions are a key issue in Japan's greying society and, although the mistake was not made under his leadership, many voters have started to question his skills in the job. Mr. Abe became prime minister following popular leader Junichiro Koizumi's decision to step down last year. ---------------------------------- Referendum? Half of the 242 seats in Japan's House of Councillors, or upper house, are being contested, with polls due to close at 2000 (1100 GMT). The first results are expected shortly after that. After a cool start to the day, hot weather is forecast which could reduce turnout as voters flee the heat and head for coastal or mountain resorts. Mr. Abe's LDP-led ruling coalition currently controls 132 seats. They need to win 64 of the seats that are up for election in order to retain their majority. The 52-year-old's ruling coalition already has a sizeable majority in the more powerful lower house -- which chooses the prime minister. Several top LDP lawmakers backed Mr. Abe in his final campaign days, emphasizing that this election was not a referendum on his leadership. But some analysts say Mr. Abe may feel he has to take responsibility for a poor result and step down. ---------------------------------- Reform plea On his final day of campaigning on Saturday, the prime minister asked voters to allow him to press on with his reform program. Addressing a crowd in Tokyo he said: ""We are a responsible party. Please give the LDP power. Do we move ahead with reform or do we go backward? We will surely push ahead."" The leader of the opposition Democratic Party (DPJ), Ichiro Ozawa, told his supporters that a win for Mr. Abe's party would mean the end of democracy in Japan. ""The upper house election is a big opportunity, and we cannot let this last chance go to waste. ""In this upper house election, if we do not get the majority of seats and the citizens let Abe continue his governance, this country will never see democracy again,"" he said. Mr. Ozawa has said that if the DPJ, together with other minor opposition parties, fails to secure an upper house majority, he will resign.