President Carter has taken a huge lead over Ronald Reagan and now shows more strength against the leading Repbulican presidential candidates then does Sen. Edward M. Kennedy, according to a new Gallup poll.

The Gallup firm, citing what it called one of the most dramatic turnabouts in its four decades of polling, said that Carter was ahead of Reagan by a ratio of 60 to 36 percent among 923 registered voters interviewed this past weekend.

The poll also showed Carter ahead of Kennedy by 48 to 40 percent among Democrats as their choice for the party's presidential nomination next year.

"The magnitude of the changes in the political fortunes of the candidates tested can be seen in the fact that Carter went from a near tie with Reagan in September to a six-point edge in mid-October to a 24-point advantage in the latest survey," the Gallup firm said in releasing its findings.

In addition, other polls frequently showed Carter trailing Reagan in trial heats and running by as much as 2 1/2 to 1 behind Kennedy among Democrats.

Carter's gains were said to be attributed to approval of his handling of the Iranian situation, to a decrease in criticism of his leadership abilities and to what the poll referred to as "overwhelming public approval of Carter's preformance in office.

Whether Carter's rise in popularity will last long is imponderable. Pollsters have long noted that there is a tendency for the public to rally around a president in a time of crisis. John F. Kennedy's highest popularity ratings, for example, were registered shortly after the disastrous Bay of Pigs invasion of Cuba. Gerald Ford showed sharp gains after the Mayaguez incident, despite the fact that more American lives were lost in that rescue than the total number of men saved.

For the short term, however, the new Gallup findings appear at least as damaging to Kennedy as they are encouraging to Carter. Many Kennedy supporters encouraged the Massachusetts senator to run against an incumbent of his own party on the grounds that Carter could not beat a Republican in 1980.

The problem with Carter, that reasoning went, was not his stand on issues but his failure to rouse the electorae. The new perception of Carter as someone who can beat the Republicans easily and the lessening of eriticism of his leadership ability strike to the heart of that rationale for Kenney's race.

Furthrmore, the Gallup poll finds a decline in support for Kennedy that is almost as dramatic as the gain in support for Carter. Three months ago, the poll notes, Kennedy led Reagan by 61 to 33 percent and placed ahead of Ford in trial heats by 58 to 38 percent. In the new poll, Kennedy edges Reagan by 49 to 44 percent but trails Ford by 43 to 51.

Carter, on the other hand, trailed Ford three months ago by 42 to 51 in a Gallup poll but now leads him by a striking 57 to 39 percent. (Ford has said he will not be an active candidate but that he would accept a draft.)

The poll attributes part of Kennedy's decline to a "negative reaction" to the senator's recent statements about the Iranian situation and the shah.

In related developments, the National Organization for Women (NOW) executive board has unanimously agreed to oppose President Carter for reelection while Newark Mayor Kenneth Gibson announced his support of the president.

Gibson said yesterday Carter "has done an outstanding job" as president.

The action by the 28-member NOW board, taken last weekend in New York, leaves open which candidate its political action committee will endorse, a decision that will be taken in Janurary.

Carter was opposed for failing to deliver on his promises to women, and some board members said they would not vote for the president even if he were the Democratic nominee and the Republican nominee opposed NOWS's goals.

"I can't conceive of any circumstances under which I would support Carter," said Ann M. Gannon of Gulfport, Miss.

Another board member, Pat HILL OF texarkana, Ark., said Carter "did have his defenders" in the group who said many women in their regions would support him. The board's vote left the NOW political action arm free "to do what's politically expedient" later, she added.