The scandal surrounding alleged unfair hiring practices in South Korea's National Election Commission is growing.

Jeon Hyun-heui, chair of the Anti-corruption and Civil Rights Commission, told a press briefing Tuesday that it has embarked on an investigation into unfair hiring practices in the election commission, following complaints filed with the civil rights authorities.

The investigation will run until the end of June, Jeon said.

At least 11 officials at the commission have allegedly recruited their sons or daughters as experienced hires, according to news reports.

Those under suspicion include high-ranking officials such as NEC Secretary-General Park Chan-jin and Deputy Secretary General Song Bong-sup, as well as working-level employees. Park and Song offered to resign immediately after the speculations came to light on Thursday.

According to the NEC data revealed by Rep. Lee Man-hee of the ruling People Power Party, the family members of the NEC employees were promoted to a higher grade -- to scale 9 under Korea's civil service system -- in around a year or even less. Lee's revelation also indicated that Secretary General Park was the final decision-maker of at least four such experienced hires, including his own daughter.

National Election Commission Chairman Rho Tae-ak told reporters Tuesday he would conduct an all-out internal inspection before his own press briefing Wednesday.

Individuals hired under such circumstances rose to 75 in 2022, up threefold from 2018, while those hired in regular hiring sessions reduced from 110 of 2018 to 77 of 2022.

The issue of unfair hiring is taken seriously in Korea's competitive society, especially for public-sector jobs like in the NEC where there are often higher bars to entry than for private-sector jobs.

Under the Korean rules -- which replaced NEC's code of conduct upon enactment -- a Korean public-sector official must report to the chief of his workplace within 14 days if his or her family member applied to get a job in the same workplace. No such reports were filed with Rho, according to Lee of the People Power Party