Prime Minister Yukio Hatoyama faced a new scandal Monday when it was revealed he failed to declare income from stock sales, giving the opposition ammunition heading into a three-day Lower House Budget Committee session.

"This is a personal affair of the prime minister," Chief Cabinet Secretary Hirofumi Hirano told reporters in an apparent attempt to contain the fallout.

Earlier in the day, reports swirled that Hatoyama did not declare ¥72 million in income obtained through stock sales in 2008.