High-tech facial masks produced by a Japanese firm have been selling like gangbusters since the outbreak of Middle East respiratory syndrome in South Korea in May, and its already intensified production capacity can't keep up with demand.

"The sales of our mask rose drastically after May 20" following the report of the first confirmed MERS patient in South Korea, Tsuyoshi Nakagawara, president of Nippon Clever Co. in Toyohashi, Aichi Prefecture, told The Japan Times on Thursday.

Nakagawara said it sold roughly 100,000 of its hand-made Pittarich masks between May 20 and June 10, a tenfold increase compared with the same period last year.