Reports from Japan say the Social Democratic Party, the SDP, is to end its alliance with the governing Liberal Democratic party of Prime Minister Ryutaro Hashimoto.

The Japanese news agency, Kyodo, said the SDP decision was based on differences over defence ties with the United States and anti-corruption measures.

Another ally of the government, the New Party Sakigake, is also scheduled to withdraw its support.

Political analysts say the Social Democrats had been expected to leave the alliance before July's elections for the upper house of parliament, so as to make their own appeal to voters.

Their departure is not expected to have much impact because the ruling party has enough support to push through important legislation.