Apparently confident in the lobbying blitz it has mounted, the White House insisted yesterday on moving toward a showdown over legislation to implement the Panama Canal treaties.

House Democratic leaders said they had wanted to take the bill off next week's schedule because they don't think they can muster enough votes to pass it, but the administration was unwilling to accept a delay.

"The White House insists we take it up next week, based on the fact that they have a well-planned propaganda campaign scheduled and paid for," said Rep. Carroll Hubbard Jr. (D-Ky.), chairman of the House Merchant Marine subcommittee on the Panama Canal and a deputy whip.

According to Hubbard, the blitz will include calls to House members from former president Ford, movie actor John Wayne and former secretary of state Henry A. Kissinger. Other aspects, Hubbard said, will include newspaper ads and a meeting at the White House next Monday night for 100 House members.

House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.) confirmed that he had taken the legislation off the calendar, but the White House asked that it be put back on for Tuesday, and this was done.

While O'Neill did not say a lack of votes was the reason for seeking delay, sources said administration supporters are slightly short of votes for passage."The White House seems to be looking at this from the perspective of what [White House aide] Anne Wexler's operation is going to do rather than from whether the vote count is there," one souce said.

Meanwhile, the Panama Canal subcommittee continued hearings on alleged Panamanian involvement in smuggling guns to the Sandinistas attempting to over throw the regime of Nicaraguan President Anastasio Somoza.

Panel sources said they had been told privately by the State Department that the U.S. Ambassador to Panama, Amber Moss, had spent five hours earlier this week trying to dissuade Panamanian Gen. Omar Torrijos from breaking off relations with Nicaragua and formally recognizing the Sandinistas.

Publicly, Lt. Gen. Gordon Sumner Jr., who retired in May as chairman of the Inter-American Defense Board, testified that Torrijos told him two years ago of his support of the Sandinistas "and his support of their efforts."

Sumner said he resigned because of his differences with people in the Carter administration, who, he claimed, were trying to make leftists into "white hats." He charged that Torrijos was under the influence of "Communists-Marxists" within Panama and Cuba. He said Panama was "an unreliable and indeed dangerous partner," and contended that the treaties should not be implemented.

But Lt. Gen. Dennis P. McAuliffe, commander of the U.S. forces in the Canal Zone, said, "The Panamanian involvement appears directed more against the Somoza regime, which is perceived as repressive, than toward advancement of the Sandinista cause. Gen. Torrijos and President Somoza have made no secret of their hostility toward each other."

McAuliffe admitted that Panama had given the Sandinistas moral support and permitted the formation of a volunteer brigade to fight alongside them, though he doubted it had done much fighting. He said Panama has also given asylum to rebels and refugees from Nicaragua.

On the charge made Wednesday, that the government of Panama sanctioned or was involved in gun running to the Sandinistas from Miami arms dealers through a Panamanian company, allegedly headed by Col. Manuel Noreiga, head of Panamanian intelligence, McAuliffe would not comment. He said only that Panamanian President Aristides Royo has assured the United States an investigation would be made.

Deputy Assistant Secretary of State Brandon Grove said "it would be contrary to the interests of the U.S. to allow Panamanian attitudes with respect to Nicaragua to jeopardize the prompt passage of implementing legislation."

The treaties do not govern the conduct of relations by Panama or the United States with third countries, Grove said. He said we would "not tolerate" an attempt by Panama to use the treaties to influence our foreign policy and Panama would reject any such attempt on our part.

Grove said operation of the canal "would be impaired and perhaps suspended" if the House rejects legislation to implement the treaties.

Basically, the two days of hearings gave right-wing opponents of the implementing legislation further ammunition in their fight, though how much effect the hearings will have on the already endangered measure is not clear.

Sumner accused Torrijos of "arrogance and contempt for the U.S." in stirring up trouble at this time. But McAuliffe said the Pananian government had been more cooperative since the Senate Approved the canal accord than ever before. He warned that hostile reactions might occur if the implementing legislation is not passed.

The legislation provides for an orderly transfer of property to Panama and operation of the canal by a joint U.S.-Panama Commission for 20 years. Then it will be turned over to Panama. Right-wing leaders want Panama to pay for the transition and object to the $800 million in costs the United States will bear.

Costs and the emotional argument against giving up the canal are causing difficulties among House members, who are receiving much mail on the issue. CAPTION: Picture, LT. GEN. GORDON SUMNER JR. . . . calls Panama "unreliable" partner, By James K. W. Atherton - The Washington Post