The Senate leadership and the White House were looking for ways last night to speed up the meandering debate on the Panama Canal treaties, but they both feared that treaty opponents retain the ability to stall the proceedings.

Treaty supporters expressed dismay yesterday that opponents had introduced 10 new amendments (some of them almost identical to each other) late Tuesday, all to the first article of the first treaty under consideration. Proponents saw this as a deliberate stalling tactic.

Sen. James B. Allen (D-Ala.), the leading treaty opponent and principal sponsor of the 10 amendments, said he might not call them up for debate, but wanted to have them in reserve in case the Senate votes later to close off debate before Allen is ready to let it end.

President Carter met with key associates in the canal treaties fight at the White House late yesterday. Aides said Carter was to be briefed on the most recent head counts in the Senate and the tactical problems facing the leadership in bringing the debate to a conclusion.

Robert C. Byrd (D-W. Va.), the majority leader, said that he might call the Senate into session six days a week, for 12 hours a day or more, if the treaty debate does not pick up speed. Byrd also threatened to cut short the Senate's scheduled 10-day Easter recess.

One administration official whose job is to lobby Congress for the White House said yesterday, "people are running out of patience" in the Senate. The administration shares with Byrd a concern that this year's heavy legislative schedule could be hopelessly disrupted by prolonged canal treaties debate.

However, both Byrd and the White House agree that they do not yet have 67 hard votes for the treaties -- the number needed to approve them if all 100 senators vote. Treaty proponents are concerned that any effort to accelerate the debate may alienate one or two senators whose support might be crucial in the final votes.

In another attempt to win over a few more votes, the State Department agreed to send to the Senate this week a draft of implementing legislation that will be submitted formally if the treaties are approved. This legislation has become a subject of controversy since it will spell out financial and other arrangements for turning over the canal to Panama that some senators have expressed doubt about during the debate.

An administration official said it was "unprecedented" to send up such implementing legislation for a treaty before it has been approved.

Well placed sources said Byrd is trying to devise some parliamentary tactic that could speed the debate, but that this may not be possible. The leadership is said to feel that an attempt to invoke cloture -- that is, vote to cut off debate -- could backfire, and that other obvious parliamentary devices are either dangerous or not usable in this situation.

This leaves Allen and his allies with the initiative, or at least the ability to dictate the Senate's timetable.

Allen said last night he had warned Byrd that the debate would be prolonged for a week if the Senate insisted on considering the two Panama treaties in what Allen considers reverse order. Allen lost a vote to put the treaties in the order he favored, and now, he said, he intends to make his prediction of an extra week come true.

Allen also recalled Byrd's original prediction that the treaty debate could last five weeks, and noted that debate has gone on just more than two weeks so far. "I think they're jumping to conclusions." Allen said of those who accused him of stalling.

On the other hand, he did not rule out the possibility that he might use stalling tactics later. And he said: "I'm not committed in blood not to filibuster." (Allen has said publicly that he did not think it would be appropriate to filibuster on the treaties.)

On the floor yesterday the Senate rejected two of Allen's amendments. One would have postponed final transfer of the canal to Panamanian control for up to 60 days if the United States were at war on the date in 1999 when the transfer is scheduled to take place. This was defeated, 57 to 38.

The second amendment would have stated in the treaty the United States right to stop any ship belonging to a hostile power in wartime from entering the canal. It was beaten, 60 to 34.

There are about 60 amendments to the two treaties still pending, though it is not certain that their sponsors will call them up for debate.

The rhetorical high point of yesterday's debate -- and perhaps of the entire proceedings on the treaties -- was a speech by Sen. Thomas H. McIntyre (D-N.H.) announcing his decision to vote for the treaties. Even treaty opponents praised McIntyre's address.

"Despite the threats of political reprisal from the redical right," McIntyre began, "I intend to vote to ratify" the treaties.

McIntyre said, "The techniques used [by the radical right] to exploit the issue of the canal treaties are the most compelling evidence to date that an ominous change is taking place in the very character and direction of American politics."

He identified his two principal opponents in New Hampshire with the radical right -- Gov. Meldrim Thomson and William Loeb, publisher of the Manchester Union Leader.