The family of veteran lawmaker Kunio Hatoyama, who died in 2016, has been found to have failed to declare some ¥700 million in taxable inheritance, according to sources.

The Tokyo Regional Taxation Bureau found the discrepancy last year. Hatoyama's family is believed to have excluded the late lawmaker's loans to his fund management body from inherited property by error, the sources said Monday.

Hatoyama held numerous Cabinet positions, including the internal affairs, justice, labor and education portfolios. His brother, Yukio, was prime minister from 2009 to 2010.

According to a report by Hatoyama's fund management body, Shinseikai, it had received loans totaling ¥450 million from the politician before it was dissolved following his death.

The family also mistakenly underestimated the value of real estate, the sources said.

The family has already paid some ¥200 million in back taxes and penalties, they said.

Hatoyama, who died in June 2016 at the age of 67, was a scion of a prominent political family. He had been given massive assets by his late mother, Yasuko, whose father founded tire-maker Bridgestone Corp.

Hatoyama's wife and three children are believed to have inherited more than ¥10 billion in total.