Amid growing speculation that former UN Secretary General Ban Ki-moon will look to run for presidency in his home country, the 72-year-old former career diplomat, who could be the best hope for South Korean conservatives to take back control of the Blue House, is now facing embarrassment over bribery allegations levied against his family members, ahead of his arrival in South Korea on Thursday afternoon.

Ban’s younger brother, Ban Ki-sang, and his nephew, Bahn Joo-hyun, have been charged in New York with conspiracy to bribe a Middle Eastern official from an unnamed country.

Prosecutors said the father and son's bribes were given to coax the official into using state funds to invest in their construction project in 2013.

Meanwhile, the former UN chief himself has also had his own name dirtied by reported links to a suspected bribery case, after Seoul-based magazine Sisa Journal recently claimed that Ban received around 230,000 US dollars from a South Korean entrepreneur when he was serving as foreign minister. The media cited an anonymous source on the report, which Ban’s spokesperson has denied, saying the allegations are “utterly untrue.”

Ban has filed a complaint over the report, and he is awaiting a ruling from a press arbitration panel.

It is expected that Ban will speak to the press as soon as he arrives at Incheon airport in South Korea on Thursday afternoon.

South Korean politics is now gearing up for a possible early election, with focus growing on potential contenders for the presidency, should the Constitutional Court decide embattled President Park Geun-hye is guilty over the influence-peddling scandal, which has seen her confidante Choi Soon-sil accused of meddling in state affairs. South Korean law stipulates that presidential elections must be held within 60 days of a president resigning or being removed from office.

Ban, one of the most high-profile names being put forward by the media, has not clarified if he would compete for the presidency, but has said he will discuss the situation of his home country with local political leaders and close friends.

Ban was working as a top South Korean diplomat before starting his tenure at the UN in 2007. He now has no party affiliation. South Korean media has speculated that he could have been set to join the ruling Saenuri Party, but the party currently finds itself embroiled in the recent political scandal. Recently, the Saenuri has witnessed a schism, with some members resigning from the party due to the political scandal.

As the Saenuri has become a less viable platform for a presidential candidate, it is hard to say if Ban would join the party or consider other options. A major South Korean political party breaking and regrouping would not be an unprecedented move.