In an apparent attempt to sway sagging British public support for any U.S. move to oust the Iraqi president, Rice told the British Broadcasting Corp. the U.S. believes it has a ''moral case'' for removing the Iraqi leader.
There is mounting speculation the United States soon will launch a military campaign to remove Saddam.
''This is an evil man who, left to his own devices, will wreak havoc again on his own population, his neighbors and, if he gets weapons of mass destruction and the means to deliver them, all of us. (It) is a very powerful moral case for regime change,'' she told BBC radio. ''We certainly do not have the luxury of doing nothing.''
Iraq has offered conflicting signals in recent weeks about allowing the return of U.N. weapons inspectors who have been refused access for four years after leaving in advance of U.S. and British airstrikes.
Echoing President Bush, Rice said that Saddam's pursuit of chemical, biological and nuclear weapons in defiance of its disarmament pledge after the 1991 Gulf War was a powerful case for a regime change.
''He has used chemical weapons against his own people and against his neighbors, he has invaded his neighbors, he has killed thousands of his own people,'' Rice said in the interview for the BBC's Sept. 11 anniversary radio series, ''The Diplomatic Jigsaw''.
''He shoots at our planes, our airplanes, in the no-fly zones where we are trying to enforce U.N. security resolutions.''
''Clearly if Saddam Hussein is left in power doing the things that he is doing now this is a threat that will emerge, and emerge in a very big way,'' she said.
''History is littered with cases of inaction that led to have grave consequences for the world. We just have to look back and ask how many dictators who ended up being a tremendous global threat and killing thousands and, indeed, millions of people, should we have stopped in their tracks,'' she added.
Brent Scowcroft, who served as national security adviser to the first President Bush during the Gulf War, cautioned against taking on Saddam with the war on terrorism in progress.
''...the central point is that any campaign against Iraq...is certain to divert us for some indefinite period from our war on terrorism. Worse, there is a virtual consensus in the world against an attack on Iraq at this time,' Scowcroft wrote in Thursday's Wall Street Journal.
Rice rejected criticism that any action against Iraq would worsen the situation in the country and said the West would have an obligation to improve life for ordinary Iraqis.
''I would think that at the end of any action that we might take toward regime change, it would be an obligation for all of us to make certain that things are better for the people of the country and the people of the region.''
Menzies Campbell, foreign affairs spokesman for the opposition Liberal Democrat Party, said Rice's arguments for removal of Saddam did not stand up under international law.
''In international affairs it is not enough to claim a moral authority in cases where the United Nations has been involved,'' he said.
''There will be no world order if the most powerful states are entitled to remove other governments at will. There is no doctrine of international law which justifies regime change.''
Gerald Kaufman, a lawmaker from the governing Labor Party, said in an article published Thursday in the Spectator magazine that there was broad opposition in Parliament to a strike against Iraq.
''(Prime Minister) Tony Blair would find it difficult to support and participate in a war against Iraq whose majority in the House of Commons was provided by the (opposition) Conservatives,'' Kaufman said.
He argued that the ''hawks'' in the U.S. administration were giving the president poor advice.
''Bush, himself the most intellectually backward American president of my political lifetime, is surrounded by advisers whose bellicosity is exceeded only by their political, military and diplomatic illiteracy,'' Kaufman wrote.
A poll published Monday in The Daily Telegraph found that 28 percent of Britons thought that the United States would be justified in attacking Iraq, while 58 percent disagreed. If the United States does strike, only 19 percent thought that Britain should join in the military action.