On the heels of several high court rulings that the December poll that returned his party to power was unconstitutional and in some cases voided local-level results, Prime Minister Shinzo Abe said Thursday that "he will work to resolve" the vote weight disparity compromising the electoral system, but gave no timeline.

Later in the day, Abe received a recommendation from a Diet panel to reduce the number of seats in the Lower House, while his Liberal Democratic Party-New Komeito ruling coalition agreed to seek comprehensive reforms, lawmakers said.

There are also vote-weight disparities affecting the Upper House, which will hold an election in June.

"The government will try to resolve the current situation as soon as possible," Abe told the Diet panel, adding he takes the court rulings seriously.

The Diet enacted a law last November to partially address the problem by trimming the single-seat constituencies in the House of Representatives to 295 from 300. But that law was not enforced in the general election that brought the conservative LDP back to power.

The Lower House panel tasked with reviewing the zoning of electoral districts is set to formally advise Abe to push the plan forward. But how quickly is unclear.

After agreeing with the recommendation, Abe is expected to immediately move to revise the Public Offices Election Law by the end of April with cooperation from the opposition.

Also Thursday, the LDP and New Komeito signed an agreement to pursue wider election reforms, including cutting the number of proportional representation seats in the Lower House to 150 from 180, and preferentially allocating 60 of those seats to smaller parties.

It is not clear whether there are plans to alter electoral zoning in the Upper House or whether the ruling coalition will address it with any urgency before July.