Justice Minister Katsuyuki Kawai resigned Thursday over his wife's alleged election violations and his own gift scandal, dealing a debilitating blow to Prime Minister Shinzo Abe who has now lost a second Cabinet member in less than a week.

Kawai, 56, stepped down little more than a month into his first Cabinet job, with the Abe administration already in damage-limitation mode after last Friday's resignation of trade minister Isshu Sugawara over a money scandal.

A lower house member elected in Hiroshima Prefecture, Kawai is the 10th Cabinet minister to resign since Abe returned to power in 2012.

Abe appointed Masako Mori, 55, a former minister in charge of addressing Japan's declining birth rate, as his replacement.

"I take responsibility as justice minister for creating a situation in which public confidence in law could be undermined," Kawai told reporters after submitting his letter of resignation to Abe at the prime minister's office.

"Neither my wife nor I was aware of (the alleged wrongdoings)," Kawai said. He vowed to get to the bottom of the allegations and explain the outcome to the public.

Anri Kawai, 46, who won a House of Councillors seat in July, is suspected of having paid staff members a daily allowance that exceeds the amount permitted, the Shukan Bunshun weekly magazine reported online Wednesday.

Her election office allegedly paid 13 female campaign announcers 30,000 yen ($276) per day, double the amount allowed. If true, the payment can be construed as bribing campaign staffers.

(Anri Kawai)

But the receipts were split across two dates -- before and during the official campaigning -- each for the maximum legal amount of 15,000 yen per day, according to the magazine, which said Kawai was in charge of his wife's election campaign.

The magazine also alleged Kawai offered potatoes as gifts to voters in his constituency.

Abe acknowledged responsibility for the past week's resignations, saying the priority now is to regain public trust.

"I feel responsible for causing this because I'm the one who appointed Mr. Kawai as justice minister," Abe told reporters. "I deeply apologize to the people of Japan."

Having served as a foreign policy advisor to Abe, Kawai has built close connections with U.S. government officials and members of Congress.

His departure came with opposition party lawmakers taking aim at education minister Koichi Hagiuda and Defense Minister Taro Kono over recent gaffes regarding students preparing for university entrance exams, and joking about typhoons, respectively.