Every few seconds, a batch of white plastic cases shoots along a conveyor belt in a South Korean factory -- coronavirus test kits destined for export around the world as the global pandemic sends demand soaring.

SD Biosensor is one of five South Korean companies whose COVID-19 diagnostic tests are being used in the country, where a huge "trace, test and treat" effort appears to have brought the epidemic under control. [...]

"Treatment for the virus begins with accurate diagnosis," company vice president Park June told AFP.

"I have been in the diagnostic industry for 35 years and never I have felt such a strong spotlight on our work," he added.

The company is already exporting to eight countries including Germany, Iran, India and Italy, and is in discussions with around 60 more, led by the United States -- which has now confirmed more cases than anywhere else in the world.

Controversy has swirled around the Trump administration's response to the outbreak, with accusations of insufficient preparations, and South Korean President Moon Jae-in said this week that his US counterpart had asked for test kits, although the White House has not confirmed the request.

Park anticipates Washington's Food and Drug Administration will grant his firm an emergency use authorisation next week, and expects the US will become its "biggest export market".