South Korean imports of Japanese beer slumped 45 percent in July from the previous month in the wake of a consumer boycott sparked by an escalating political and economic dispute between the two Asian neighbors, data showed.

The plunge is good news for rival importers and South Korean brewers but is a worrying sign for Japanese exporters like Asahi Group Holdings, which said last week the boycott was affecting sales and lowered its profit guidance.

Japan shipped $4.3 million worth of beer to South Korea in July, down from $6.6 million a year earlier and $7.9 million in June, according to preliminary customs office data provided by lawmaker Kim Jung-woo to Reuters.

Japan tightened export controls last month for materials used to make chips, South Korea's top export item, intensifying a row over wartime forced labour and sparking a consumer backlash in South Korea.

Many Korean supermarkets and convenience stores have removed Japanese items such as beer from their stands and stopped new orders.

South Korea buys 61 percent of Japan's beer exports, spending 7.9 billion yen ($73 million) in 2018 on the shipments, according to Japan's finance ministry.

South Korea's imports of Japanese beer declined 11 percent in the first half from a year earlier, after nearly quadrupling over the past three years in 2018, according to customs data.