US government prosecutors have asked South Korea to arrest a brother of former UN Secretary-General Ban Ki-moon indicted in New York on charges of bribery, an official confirmed on Friday (Jan 20).

An indictment unsealed on Jan 10 accuses Ban Ki Sang, a senior executive in a South Korean construction company, and his son Joo Hyun Bahn, a Manhattan real estate broker, over the attempted US$800 million sale of a building in Hanoi.

During a court hearing in a federal court in New York on Friday, an assistant US attorney said a request had been made for the arrest of Ban.

The suspect, who was an executive at Keangnam Enterprises, a South Korean construction company, has not yet been arrested, the prosecutor told the court.

Ban's brother stepped down from the helm of the United Nations on Jan 1, replaced by former Portuguese prime minister Antonio Guterres. Bahn is the former UN chief's nephew.

Both relatives are charged with corruption, money laundering and conspiracy.

US prosecutors allege that the international bribery conspiracy took place between March 2013 and May 2015 in relation to the attempted sale of a commercial and residential complex in Hanoi, built and owned by Keangnam.

The plot focused on an attempt to get an official from an undisclosed Middle Eastern kingdom to purchase the property.

The father and son agreed to pay an initial bribe of US$500,000, wired to an account in New York from South Korea in April 2014, followed by a payment of US$2 million upon completion of the sale, prosecutors said.

US citizen Malcolm Harris, accused of masquerading as a go-between and also indicted, pocketed the bribe which he frittered away on personal luxuries, US prosecutors say.

The sale never went through, ultimately forcing Keangnam to enter court receivership in South Korea due to a growing liquidity crisis.(Channel NewsAsia)