UNITED NATIONS — Secretary-General Ban will attempt today, in his first official press conference since assuming his post on January 1, to stem early but persistent criticism of the manner in which he has made his initial appointments of U.N. officials.

While America is pushing Mr. Ban to complete the composition of his team quickly, criticism has grown among influential Turtle Bay constituents about his intention to hand the powerful political department, currently led by the Nigerian Ibrahim Gambari, to the American ambassador to Indonesia, Lynn Pascoe.

For the political department, the best choice would be someone from “a less powerful country, a country that is more neutral” than America, the Chinese ambassador to the United Nations, Wang Guangya, told The New York Sun. (Mr. Ban has filled some key positions with officials from poorer countries, most of them women.)

Mr. Wang added that Washington itself could benefit from allowing other countries to head the political direction of the United Nations, to avoid the impression of undue influence in the international body.

“The secretary-general is not an American, and neither is his deputy,” a State Department official countered. “With over $5 billion a year, getting an American in some position is important,” the official, who spoke on condition of anonymity, said. Washington has been generally supportive of Mr. Ban’s appointments so far.

Other criticism, predictably, came from former officials loyal to Mr. Ban’s predecessor, such as the outgoing deputy secretary-general, Mark Malloch Brown.

“Kofi Annan and I in the last few years established a very open, transparent selection process that respected the fact you needed a team of all nationalities, but which went out of its way to find the right senior person for the right job,” Mr. Malloch Brown said in an interview with Britain’s Channel 4 on Tuesday.

After criticizing the appointment of a fellow Briton, John Holmes, as humanitarian coordinator, Mr. Malloch Brown added that he hoped Mr. Ban “is going to recover on this one and with his future appointments,” and that he is “going to rely on the same kind of transparent selection processes we did.”

Nevertheless, the fiercest criticism so far has come on appointments that included prominent members of Messrs. Malloch Brown and Annan’s old team, including the former chief of staff, Alicia Bárcena Ibarra, as the new undersecretary-general for management.

Ms. Bárcena, a Mexican environmentalist who has little previous management experience, said yesterday that although she was one of the U.N. representatives on Mr. Ban’s transition team, even she was surprised when her new appointment was offered. “I was preparing to go to Chile when he called,” Ms. Barcena, whose husband is Chilean, told the Sun. Surprise was also the reaction of Mr. Ban’s new deputy, Foreign Minister Asha Rose Migiro of Tanzania, who described her appointment to Dar es Salaam’s Daily News.

According to the account, the Tanzanian president called Ms. Migiro last Friday, saying Mr. Ban was looking for her. She phoned New York, and when Mr. Ban finally got on the line, he said, “Tell me if you are willing to accept the offer, because I have to make an announcement immediately.”

She had met him only briefly prior to the appointment, but nevertheless accepted, “almost as if in disbelief.”

Mr. Ban’s new spokeswoman, Michèle Montas, likewise described a quick and surprising job offer. Mr. Ban may have wanted to prevent leaks of future appointments, but his methods have left the impression of a haphazard and rash process.