Han Man-soo, the nominee for chief of the corporate watchdog Fair Trade Commission, quit earlier in the day after a local newspaper reported that he evaded taxes by holding a large amount of money in overseas bank accounts.
In the past week alone, four of Park's personnel appointments, including Han, resigned for reasons ranging from a misunderstanding of the job's requirements to an alleged sex-for-favors scandal.
Earlier this month, Park's nominee for science minister quit after expressing frustrations about a parliamentary impasse that was blocking the government from fully forming and subsequently delaying his parliamentary confirmation process.
Park's first prime minister nominee, Kim Yong-joon, was the first to go in January under pressure over a series of alleged ethical lapses, including draft-dodging by his two sons.
President Park Geun-hye. (Yonhap file photo)
This series of personnel failures has translated into mounting political pressure from both the ruling and opposition parties for Park to apologize to the nation and punish those responsible for selecting and vetting the nominees.
"As the ruling party, we cannot hide our embarrassment and shame at having to watch (nominees) resign (every time) we wake up in the morning," Rep. Lee Sang-il, the spokesman of Park's ruling Saenuri Party, said in a press briefing.
"Cheong Wa Dae (the presidential office) must feel remorse over how it has vetted personnel ... and the ruling party also feels responsible for the recurring flaws in the president's appointments and apologizes to the nation."
The spokesman called on the presidential office to strictly examine the reasons for the series of resignations and strengthen its personnel vetting system, while punishing those responsible for carelessly selecting personnel.
"If Han Man-soo created overseas bank accounts for slush funds, this would be a typical form of flight of assets, which is punishable by up to life in prison," said one lawmaker considered allied to Park. "If something like this wasn't detected, it basically means no vetting took place, which amounts to dereliction of duty on the part of Cheong Wa Dae and the office of the senior presidential secretary for civil affairs."
DUP leader Moon Hee-sang (2nd from R) speaks during a party leaders meeting in Seoul on March 25, 2013. (Yonhap)
Leaders of the main opposition Democratic United Party (DUP) stepped up their attacks.
"Including those who quit during the presidential transition period, a total of 12 people have stepped down, which is a personnel failure unseen in any previous administration," DUP leader Moon Hee-sang said at a party meeting. "President Park must apologize for the personnel disaster."
In choosing personnel, Park has often stressed a nominee's professionalism and agreement with her administrative philosophy.
However, critics have questioned whether she places as much priority on thoroughly vetting her personnel and listening to public opinion.
Some also raise doubts as to whether the newly created personnel committee at Cheong Wa Dae is serving its purpose. The committee's stated purpose was to ensure fair personnel appointments by the president.
However, sources have said the committee is run by some of Park's closest aides, including presidential chief of staff Huh Tae-yeol, which makes it difficult for them to raise objections to the president's choices.
Park is widely reported to make personnel choices almost single-handedly, often based on her past experiences of working with the potential candidates.
The exact composition and functions of the committee remain a secret apparently due to concerns about external lobbying.
"Not only should there be a replacement of the president's civil affairs aides who weren't able to properly vet (nominees), but there should also be serious consideration for changing the composition of the personnel committee, such as by including outside members," said Shin Yul, a political science professor at Seoul's Myongji University.
The professor also warned that if the president does not change her way of choosing personnel, the public may eventually abandon all trust in her.