A billionaire real estate developer from Macau was sentenced to four years in prison on Friday for bribing two diplomats, including a former president of the United Nations General Assembly, to help him build a conference center in Macau.

The corruption case was the worst financial scandal for the world body since the abuse of the Iraqi oil-for-food program more than 20 years ago. In 2016, a panel appointed by the secretary general at the time, Ban Ki-moon, recommended new ethical rules and financial disclosure standards for the president the General Assembly, who is elected on a yearly basis.

The developer, Ng Lap Seng, 69, was convicted in Federal District Court in Manhattan last July on two counts of violating the Foreign Corrupt Practices Act, one count of paying bribes, one count of money laundering, and two counts of conspiracy.

The judge, Vernon S. Broderick, ordered Mr. Ng to forfeit $1.5 million, representing the assets used in the crimes, and to pay a $1 million fine.