By Jack Kim

SEOUL (Reuters) - South Korean President Park Geun-hye's nominee for defense chief withdrew his candidacy on Friday, the latest humiliation for her month-old administration as the country faces daily threats of nuclear annihilation from the North.

The blunders with appointments began with the withdrawal of her first choice as prime minister over charges of inappropriate real estate deals even before she took office on February 25.

Park, South Korea's first woman leader, was also without a finance minister until Friday, when she finally filled the post and two other cabinet seats. Her choice for vice justice minister resigned on Thursday amid a sex scandal.

North Korea, which has made no secret of its hatred for Park and last week referred to the "venomous swish" of her skirt, has threatened to attack the South and the United States on a daily basis since she took office.

It has also been blamed for a cyber attack on commercial banks and broadcasters this week.

Retired Gen. Kim Byung-kwan withdrew his name for the post of defense chief amid opposition objections to his failure to disclose activities as a lobbyist for a defense contractor.

Park's refusal to drop Kim when the criticism first surfaced was seen as a sign of an ineffectual leader unwilling to change her mind. Critics say her private and introverted management style is taking its toll as her popularity ratings start to sag.

They say she has stumbled because of her reliance on a group of loyalists who served her well for more than a decade as a legislator but have now rendered her actions ineffectual.

Kim's decision to step aside came amid growing political pressure on her to make a move in the face of the threats from the unpredictable North.

The presidential Blue House later announced Park will keep the defense minister from the previous administration, Kim Kwan-jin, because "the situation is too urgent to be holding up time for political debate and nomination hearing" to select a new candidate.

"She made the decision so that we can focus on stabilizing a crisis situation and easing public anxiety," Park's spokeswoman, Kim Haeng, told a briefing.

Political analyst Yu Chang-seon said Park displayed a style of decision-making where she just can't seem to change her mind once she's reached a decision.

"The impact on her ability to govern has been growing considerably with the problems with appointments basically overwhelming everything," Yu said.

Park also faces challenges to Asia's fourth-largest economy from a weaker yen that has made Japanese cars and electronics more attractive than their Korean counterparts.

Park is the daughter of assassinated leader Park Chung-hee, who took power in a military coup in 1961 and ruled the country with iron fist until 1979.

Park, 61, is believed to have relied heavily on her former parliamentary aides in selecting cabinet appointees. Parliament is empowered to scrutinize prospective appointments, but cannot veto anyone but the prime minister.

Park defeated a liberal challenger at the December presidential poll promising to create new jobs and boost welfare, but she has not spelled out how she will deliver on those pledges.

She pledged to engage North Korea in dialogue to ease tensions while responding with force in the event of an attack. But experts say it is unlikely North Korean leader Kim Jong-un, still working to establish his new leadership, will come to the table on Park's terms.

(Additional reporting by Ju-min Park; Editing by Nick Macfie)