Confusion reigned among Social Democratic Party officials Wednesday after Democratic Party of Japan leader Katsuya Okada claimed he called the SDP chief and urged her party not to field candidates in April's House of Representatives by-elections and instead support DPJ candidates.

Okada told reporters Tuesday that he made the request to SDP leader Mizuho Fukushima over the phone, saying the by-elections would be a good opportunity for the opposition camp to say no to the administration of Prime Minister Junichiro Koizumi.

"If the SDP fields its own candidates, it would work in favor of (Koizumi's) Liberal Democratic Party," because the anti-LDP votes would be split, Okada said.

Fukushima denied receiving such a direct request from Okada, however. She had pledged earlier this month to field a candidate in either the Fukuoka No. 2 constituency or the Miyagi No. 2 voting district, where by-elections will be held April 24.

"I understand that our local (chapters) are discussing" the by-elections, Fukushima told a news conference Wednesday. "I have not been formally informed (of the DPJ's position) by Okada, and find it difficult to understand why he brought up the subject (with reporters) that way."

The DPJ is desperate to win the by-elections, which will be held to fill vacancies left by the resignation of lawmakers who won the seats on the party's ticket.

The Fukuoka No. 2 seat has been vacant since Junichiro Koga stepped down early last year.

Sayuri Kamata resigned from the Diet last month following the conviction of her campaign workers for election law violations, leaving the Miyagi No. 2 constituency seat vacant.