JERUSALEM (AP) _ Israel is unlikely to stage a pre-emptive strike against Iraq despite revelations that the Arab nation may have an advanced nuclear weapons program, political analysts said Saturday.

''Iraq now has missiles, and they are telling us in so many words that they will be using them if we strike,'' said Amatzia Bar-Am, an Iraq specialist at Haifa University. ''I don't think Israel would be foolish enough to start this kind of cycle of violence.''

''The situation in the Middle East has changed since 1981,'' he said, referring to Israel's bombing of an Iraqi nuclear reactor that Israel said could have been used to produce nuclear weapons. Iraq said the facility was to be used for peaceful purposes.

U.S. newspaper reports, citing classified CIA material, have said Iraq has positioned missile launchers in the western part of the country, within range of Tel Aviv.

The Israeli government has not commented following Wednesday's arrest in London of five people in an alleged plot to smuggle nuclear weapons triggers to Iraq.

''We have no comment on it. It's something that happened between England and Iraq,'' Foreign Ministry spokesman Yossi Amihud said Saturday. Aides to Prime Minister Yitzhak Shamir have also refused to comment.

Political observers said Israel's verbal restraint was a sign that it did not want to escalate tensions with Iraq, one of its most implacable enemies in the Middle East.

Iraq, meanwhile, has accelerated its rhetoric. Responding to the arrests in Britain, Iraq's deputy foreign minister, Nizar Hamdoun, said ''the current British campaign is trying to provide the groundwork for an Israeli aggression against Iraq, reminding us of the year 1981.''

But Bar-Am said another strike was unfeasible. He noted that in 1981 the Osirak nuclear reactor near Baghdad provided a clear target for Israeli warplanes, but Iraq's current nuclear program is spread across the country.

''There is no easily identifiable target that you hit and then get rid of the whole nuclear option,'' he said. ''There doesn't seem to exist anywhere an atomic reactor.''

Israeli military analysts have estimated that Iraq is less than five years away from developing nuclear weapons and that it was making rapid strides in producing other unconventional weapons.

''They are making an effort, not only in the nuclear field, but also with regards to missiles, to chemical weapons and to biological weapons,'' said Zeev Eitan, a senior analyst with Tel Aviv University's Jaffee Center for Strategic Studies, in an interview with Israel radio broadcast Saturday.

Political analysts agreed with Bar-Am that hostilities between Israel and Iraq were unlikely in the near future because of mutual deterrence, but warned that a major crisis in the Middle East could set off a confrontation between the region's two mightiest military powers.