UNITED NATIONS – The United Nations Security Council is about to rotate five of its members and the new composition looks positive for America, diplomats say.

Tomorrow, five new members will be voted in, and by January 1 they will take their seat on the 15-member council. The most significant change will be that Germany, which has led an ambitious agenda in its two years as an elected member, will rotate out, and Japan, a strong American ally, will join the council.

“Having the Japanese will be welcome,” said the spokesman for the American U.N. mission, Richard Grenell. America works “extremely closely” with Tokyo, he said, pointing out that after America, Japan is the largest donor to the U.N. budget.

Two European countries on the council, Germany and Spain, will be replaced by Denmark and Greece, while Japan will represent the Asian group instead of Pakistan. Chile will give way to Argentina as the South American representative, and Tanzania will take Angola’s seat as a member of the African group.

Five other elected members, Algeria, Benin, Brazil, the Philippines, and Romania have another year as council members. America, Russia, Britain, France, and China have permanent, veto-yielding seats.

“Germany was a heavyweight,” said the Russian ambassador, Andrey Denisov. “They were trying to pose as an ambassador for all those who are not members of the Security Council.”

A European diplomat who follows the council closely but refused to be identified, said that the main change in the council in the last two years was the emergence of a bloc, largely led by Germany, that challenged the permanent members, known here as the P-5, by giving more weight to the elected members, or E-10.

This was most pronounced in the months leading up to the 2003 Iraq war, when the E-10 met frequently, quite often in the German mission, creating a powerful war-opposing bloc. By using a rule that allows only resolutions that get nine supporters to get to be voted on, the E-10 were able to create their own “veto power,” the European diplomat said.

It was that power, in addition to the French threat of using its own veto, which blocked what was known in the council as “the second Iraq resolution,” meant to give an explicit permission for military action. When Spain changed governments last year, the opposition to the Bush administration on that council group became even fiercer.

Spain now will be replaced by Greece, which is “a wash” as one diplomat put it. Denmark, a mild supporter of the Iraq war, is mostly interested in human rights issue and is not expected to be as ambitious a leader in the E-10 as was Germany.

With Japan, a certified member of the “coalition of the willing,” as the new heavyweight in the E-10, the assumption is that America will benefit.

On one issue, however, America might end up missing Germany, which was most helpful in averting numerous attempts for anti-Israel council resolutions, some of which ended up in an American veto.

“For us, the biggest loss is Germany,” said Israeli ambassador, Dan Gillerman. In important European group, he added, Germany and Britain were the counterweight to others who were pushing a more pro-Arab agenda.

Pakistan is another heavyweight that is now leaving the council. As a powerful representative of the Islamic bloc it created a lot of problems for America, and even for Russia, which last week met its match in Pakistani ambassador Munir Akram, who was successful in watering down an antiterrorism resolution introduced by Moscow.

“Indians and Pakistanis, they are born multilateral diplomats,” Mr. Denisov said in a nod of appreciation to Mr. Akram. Even diplomats from archnemesis India said their fears did not materialize in Pakistan’s two year stint.

“Anyway, we would rather look forward,” said Anand Sharma, a visiting member of Parliament from the ruling Congress party. “For us the most important thing is reform, so we are glad Japan is in.”

Along with India, Germany, and Brazil, Japan is expected to push for a change in the U.N. Charter, which would expand the council and give them permanent seats that would better reflect the current world power structure, as opposed to that which existed after World War II.