NHK has learned that offices of some lawmakers of Japan's main ruling Liberal Democratic Party who exceeded their fundraising ticket sales quotas may have kept the extra revenue instead of giving it to their factions.

Sources say this concerns the offices of lawmakers of the LDP's largest Abe faction and the Nikai faction.

Tokyo prosecutors searched the two factions' offices on Tuesday on suspicion of violating the political funds control law.

The factions are suspected of paying kickbacks to the offices of members who sold fundraising party tickets in excess of their quotas, without recording the amount as revenue in their political fund reports.

The unreported money collected by the Abe faction over a five-year period through 2022 likely adds up to about 500 million yen, or about 3.5 million dollars. For the Nikai faction, it is expected to total about 700,000 dollars.

Observers say the total amount of unreported income from fundraisers could rise further.