The Cabinet on Friday approved a bill to bring about the country's largest ever change to the distribution and boundaries of Lower House single-seat districts to rectify a vote-value disparity that the Supreme Court says has generated a "state of unconstitutionality" in national elections.

The revision to the Public Offices Election Act would include adding 10 single-seat districts to five prefectures, while cutting one each from 10 prefectures, with an eye to narrowing the vote disparity below the twofold level between densely and sparsely populated districts.

In all, the changes would affect 140 single-seat districts in 25 prefectures.