SoftBank Group Corp CEO Masayoshi Son said he has secured a monthly supply of 300 million face masks for Japan after reaching a deal with Chinese electric vehicle maker BYD Co. Ltd., which has retooled to make them.

From next month, SoftBank will supply two different kinds of mask, initially for medical staff, in cooperation with the Japanese government's "mask team" that was set up to address shortages caused by the coronavirus pandemic, Son said on Twitter.

SoftBank, which last month said it was donating 1.4 million masks to New York state, will supply the masks without taking a profit.

"Softbank will work with the government to supply masks to the medical community, and to as many people as possible," he said.

Addressing the supply crunch is a priority for the government, which will begin delivering two washable masks to households next week — a move that has been widely criticized on social media as inadequate.

The government is also targeting domestic production of 700 million disposable masks per month.

Son, who has a long history of partnering with and investing in Chinese firms, said BYD is setting up a new line to produce the masks.

BYD's production capacity has reached 15 million masks a day, a company spokeswoman said, confirming the firm will supply masks to SoftBank.

SoftBank's supply will consist of 100 million N95 masks, which can filter very small particles, and 200 million regular surgical masks.

The coronavirus pandemic has spurred Son's return to Twitter, where he complained that Japan's response is being spearheaded by politicians rather than scientists. He also surveyed people on their view of the government's response, adding to pressure to increase social distancing measures.

Last month, he tweeted that he would donate coronavirus testing kits to 1 million people, but later said he would donate 1 million masks instead.