The Senate Foreign Relations Committee was expected to vote Tuesday on the nomination of Bolton, a sharp-tongued conservative known for using brusque language to describe the U.N. and individual nations.
The meeting came amid complaints from Democrats that they did not have enough time to investigate the latest in a string of allegations against Bolton. Democrats on the panel had repeatedly asked for delays in the vote.
A spokesman for committee chairman Richard Lugar, R-Ind., said Lugar saw no reason to delay the vote.
"I do not think the concerns raised about Secretary Bolton warrant our rejection of the president's selection for his own representative to the U.N.," Lugar said in a statement prepared for Tuesday's session.
White House press secretary Scott McClellan said there was no need for delay.
Asked if the president had any reservations about Bolton's fitness for the post, McClellan replied: "Absolutely not."
Bolton has addressed all questions about his record and behavior by testifying before the committee and offering additional answers to the panel in writing, McClellan said.
Democrats hoped to defeat Bolton but were outnumbered 10-8 on the committee.
Several Republicans have made it clear they have reservations, that the president could have chosen someone better for the post, but it would be extraordinary for a Republican to vote against one of the Mr. Bush's nominees, reports CBS News Capitol Hill Correspondent Bob Fuss.
At least one Democratic senator, Sen. Christopher J. Dodd, D-Conn., said he would ask for a closed session so the committee could hear from intelligence officials about information Bolton requested relating to National Security Agency communications.
According to a spokesman for Dodd, Bolton asked for and received the identities of 10 U.S. officials involved in such secret NSA interceptions during the past four years.
Democrats also wanted more information about Bolton's dealings with a female employee during his time at the Justice Department in the late 1980s. The two clashed over the woman's request for extended maternity leave.
Bolton is a harsh critic of the United Nations bureaucracy and thus a provocative choice to be Washington's representative to the world body. Most of the allegations that have accompanied his nomination, however, concern his personal dealings and judgment.
The allegations attempted to paint Bolton as an imperious hothead who dressed down junior bureaucrats and withheld information from his superiors in his current job as the State Department's arms control chief.
There were repeated questions by senators at his confirmation hearing last week concerning what Bolton may have done to punish or pressure underlings who crossed him. A senior colleague called him a "serial abuser."
Bolton denied he did anything improper, but said he had "lost confidence" in two intelligence analysts who disagreed with him.
Bolton, 56, has served four years as arms control chief at the State Department, but he is not a diplomat by training. He was an assistant attorney general in the Justice Department under Bush's father, President George H.W. Bush, and held other government jobs during the Reagan administration.
A Yale Law School graduate, Bolton has been a lawyer in private practice and an academic.
He is considered one of Mr. Bush's most conservative advisers on foreign policy, and one of the most caustic.
He has said, for example, that the loss of 10 stories from the United Nations headquarters building in New York would make no difference.
When the State Department was trying to move toward accommodation with North Korea over its nuclear program two years ago, Bolton called the country's leader, Kim Jong Il, a "tyrannical dictator."