Fines for parking offenses involving foreign diplomats based in Japan were collected in only a quarter of cases last year as they were protected by diplomatic immunity, according to the National Police Agency.

Police spotted around 2,600 vehicles with diplomatic license plates illegally parked in 2019, with drivers not paying fines in about 75% of cases, an NPA official told the Diet on Thursday.

In 2018, parking offenses involving vehicles with diplomatic license plates stood at 3,948, the NPA official added. As of Wednesday, the Foreign Ministry has issued 1,982 special license plates for diplomats stationed in Japan, according to the ministry.

The NPA official said it is difficult to collect fines from diplomats as they have immunity based on the Vienna Convention on Diplomatic Relations.

The police collected fines in about 81% of cases of parking violations committed by ordinary drivers in the country in 2019, he added.

Opposition lawmaker Shinkun Haku, who asked about the figures during a session of the House of Councilors Committee on Foreign Affairs and Defense, described the failure to pay as "a big problem" and criticized the offenders.

Foreign Minister Toshimitsu Motegi said at the session that the parking offenses were "extremely regrettable" and that his ministry will continue to warn foreign diplomats in Japan to comply with traffic rules in the country.

However, the foreign minister did not directly respond when Haku, a member of the main opposition Constitutional Democratic Party of Japan, proposed that the government disclose the names of the countries involved or ask for the license plates to be returned in the case of habitual offenders.