Individuals with overseas assets worth more than ¥50 million must report them to the nation’s tax authorities or face tough penalties, according to new government regulations introduced ahead of this year’s tax return filing.

Taxpayers who fail to report these assets face penalties of up to a year in prison or a maximum fine of ¥500,000, according to the National Tax Agency.

People affected by the new regulations are those holding assets overseas, including savings and deposits, real estate, securities, precious metals, accounts receivables and artworks, whose combined total exceeds ¥50 million as of Dec. 31, 2013. They must report details on such assets to their local tax bureau by March 15.

Non-Japanese residents are also subject if they have lived in Japan for more than five years within the past 10 years.

“Overseas assets” cover securities and investment trusts issued in Japan by foreign capital companies, including yen-dominated samurai bonds. Securities and bonds Japanese companies issue abroad, on the other hand, are excluded from the reporting obligation.

The new regulations are aimed at curtailing tax evasion involving assets overseas. The number of undeclared overseas assets stood at 111 in fiscal 2011, up from 78 in fiscal 2007.

The amount of money taxed on undeclared income also rose to ¥7.2 billion in 2011, compared with ¥6.7 billion in 2007, the agency said.