TOKYO, Aug. 29. (Xinhua) -- Shipments from Japan to South Korea of a chemical now subject to tighter export controls plummeted in July from a month earlier, the government said in a report on Thursday, as ties between both countries continue to be strained.

According to the Finance Ministry, shipments to South Korea of hydrogen fluoride tumbled 83.7 percent to 479 tons in the recording month, as a result of Japan's tighter export controls.

In terms of the export value, the ministry said it also fell 32.6 percent to 400 million yen (3.78 million U.S. dollars), in a sign the tightening of controls, which came into effect from July 4, on three chemicals bound for South Korea, are having significant financial ramifications.

Hydrogen fluoride is one of three chemicals Japan decided would be subjected to stricter export controls, with Tokyo citing national security reasons for the move, although it is widely believed to be a response to a wartime labor dispute between both countries.

Under the new restrictions, Japanese manufacturers now have to file individual applications for exports to South Korea of fluorinated polyimide, hydrogen fluoride and resists.

These products are are commonly used in smartphone displays and chips, mainstays of South Korea's tech-forward economy and integral to some key supply chains that flow from Japan and through South Korea onward.

Regarding shipments and export values of the other two materials, the Finance Ministry here does not have individual data, although South Korean manufacturers like Samsung Electronics Co., and others involved in the semiconductor and display business, are likely to be hurt by Japan's stricter controls, economists have said.