Japan began distributing reusable cloth face masks on Friday dubbed "Abenomasks" after Prime Minister Shinzo Abe, whose decision to issue two per household has been met with mockery by some.

Abe announced the measure on April 1 as part of a wider package of emergency policies to tackle the coronavirus pandemic, saying the delivery of cloth masks would help ease a nationwide shortage.

But the decision attracted ridicule, particularly given the scanty size of the coverings. They sit over a much smaller portion of the face than disposable surgical masks that have become ubiquitous in Japan in recent months.

The cloth coverings have become widely referred to as "Abenomasks", meaning "Abe's masks" and a play on the prime minister's much-touted "Abenomics" economic programme.

About 50 million households across the country will receive two masks each, delivered by Japan Post.

At a post office distribution centre in Tokyo on Friday, the first sets were going out for delivery to parts of the city with the highest number of virus cases.

"We'll be delivering the masks without any physical contact with the customer, just putting them in letter boxes," said Japan Post official Hideo Aoyama. 

"A lot of people are waiting for these masks, so I'll be delivering them as quickly as possible," added postman Taketo Nishiwaki. 

Shortage

The programme is expected to cost 46.6 billion yen ($435 million), which some have criticised as a waste of taxpayer money, with commentators noting people can make masks at home.

But others said the cloth coverings will be helpful given the ongoing shortages.

"I guess it won't hurt because you can wash them and reuse them and you can block your coughing and droplets by wearing them," 26-year-old Yohei Ono told AFP.

"But I have to say it's very small as public support goes."

Online retail sites have moved quickly to ensure the cloth masks do not end up for resale on their platforms, with two popular forums Mercari and Yahoo Japan banning users from selling them.

Face masks are not obligatory in Japan but were commonly worn during cold and hay fever seasons even before the coronavirus outbreak.

Japan still has relatively few cases of the virus, with around 9,100 infections and 148 deaths recorded so far, but on Thursday Abe expanded a month-long state of emergency to cover the entire country.

The measure had originally been put in place for seven regions with the highest number of infections. 

"It's very late. The government should have issued the state of emergency nationwide when it declared it for the seven prefectures," said Shoichi Inoue, 58, a warehouse worker.

"The state of emergency may also be extended after May 6. That is worrying, too."