South Korea's environment ministry said Friday that it will tighten radioactive and heavy metal tests on imported battery, tire and plastic wastes, apparently targeting Japan in protest against Tokyo's export curbs.

The ministry said in a statement that the country will intensify an environmental and safety inspection on the waste materials imported from foreign countries, including Japan, for recycling.

It noted that the decision reflected the public concerns about radioactive contamination of imported wastes.

The move followed the ministry's announcement on Aug. 8 to strengthen a radioactive and heavy metal inspection on all the coal ash imports from Japan.

The newly added waste materials under stricter inspections will be waste batteries, tires and plastics.

In 2018, South Korea imported 2.54 million tons of waste materials, about 15 times the country's export of 170,000 tons in industrial wastes, according to the ministry data.

Half of the total waste imports, or 1.27 million tons, was coal ash, followed by waste batteries with 470,000 tons, or 18.5 percent, waste tires with 240,000 tons, or 9.5 percent, and waste plastics with 170,000 tons, or 6.6 percent each.

All the 1.27 million tons of coal cash was imported from Japan alone last year, while battery, tire and plastic wastes imported from Japan amounted to 71,000 tons, 7,000 tons and 66,000 tons respectively.

The stricter radioactive tests came after Japan removed South Korea earlier this month from its whitelist of trusted trading partners, which are given preferential export procedure. In response, Seoul dropped Tokyo off its whitelist.

Public concerns deepened here about radioactive contamination of Japanese imports amid the growing local media reports about the poor management of the Fukushima nuclear power plant destroyed by earthquake and tsunami in 2011.

The Seoul ministry said it will increase the number of on-site inspections on domestic waste importers from once every three months to at least once a month.

If radioactive materials or heavy metals are spotted excessively from waste imports, those will be ordered back to the exporters, the ministry added.