Prime Minister Junichiro Koizumi said Friday his Liberal Democratic Party will require all member lawmakers to vote for a bill to revise the Imperial House Law to open the way for female monarchs.

The comments are designed to ward off persistent resistance within the LDP to allowing females and their descendants to ascend to the Imperial throne.

Koizumi rejected LDP General Council Chairman Fumio Kyuma's reluctance to submit the bill during the regular Diet session from Jan. 20 to June 18 as well as voices within the LDP against binding members to vote for it.

"There is no change," Koizumi said of the government plan to submit the bill to revise the 1947 law that allows only male heirs who have emperors on their fathers' side to reign.

Kyuma, who chairs the LDP's decision-making organ, said at party headquarters earlier in the day that he considers the bill "not as urgent as to be dealt with during the regular Diet session."

The government usually seeks the LDP's go-ahead before submitting a bill to the Diet, and LDP lawmakers are required to vote for the bill approved at the General Council unless it decides otherwise.