A former Goldman Sachs banker charged last year in connection with the looting of billions of dollars from a Malaysian sovereign wealth fund pleaded not guilty in Brooklyn federal court on Monday, just hours after being flown back to the United States.

The banker, Roger Ng, had been in custody in Malaysia since he was charged with helping the country’s former prime minister and others embezzle at least $2.7 billion from the 1Malaysia Development Berhad fund, known as 1MDB.

The magistrate judge overseeing Mr. Ng’s bail hearing, Peggy Kuo of the United States District Court for the Eastern District of New York, said both sides were engaged in plea talks. Marc Agnifilo, Mr. Ng’s lawyer, disputed that characterization after the hearing, although he left open the possibility of an agreement with prosecutors.

“Roger has pleaded not guilty and will at least consider all options available to every defendant at the inception of a case,” Mr. Agnifilo said.