A day after two small cities on the main island of Honshu reported finding cash in men's rooms in public buildings, officials from north to south Japan disclosed that they too had discovered such mysterious packages.

The unusual charity drive was a top story on national television, with media estimating that at least 2 million yen (S$25,000) has been dropped off in bathrooms.

Each envelope contains 10,000 yen (S$125) and a handwritten letter.

'Please make use of this enclosed inheritance money of 10,000 yen to fund your self-enrichment,' says each letter, which is written with a traditional brush and evokes the language of Buddhist monks.

On Wednesday, officials in Miyazaki prefecture on the southern island of Kyushu and in Sapporo on the northern island of Hokkaido said they had found similar packages in recent weeks.

'We don't know who left the money or for what purpose,' said Mr Yoshinori Sato, a spokesman for the Sapporo City Hall.

Kyodo News said that envelopes containing money have been found in more than 10 public office buildings across Japan.

While there's no telling if other people had taken the cash and kept quiet about it, all of the packages reported to the authorities were turned over to the police.

The police are keeping the cash in case someone claims it.

AGENCE FRANCE-PRESSE