America's Roman Catholic bishops will support the Panama Canal treaties and submit Senate testimony in their behalf "at appropriate time.," the head of the American hierarchy told President Carter this week.

Archbishop Joseph L. Bernardin, president of the National Conference of Catholic Bishops, made the pledge during a half-hour meeting with the President to discuss questions of human rights.

The archbishop said he had requested the White House meeting because he had "received many questions on this subject from bishops in other countries" and anticipated further questioning at the worldwide synod of Bishops that opens in Rome later this month.

Churchmen in other countries, he said, have expressed concern "about how firm and lasting the present U.S. emphasis for human rights will prove to be."

He said he came away from the White House interview convinced of President Carter's "firm and sincere commitment" to human right as a matter of national policy.

Archbishop Bernardin, who was accompanied by the Most Rev. Thomas C. Kelly, generally secretary of the CAtholic hierarchy, said he volunteered Catholic support on the Panama Canal treaties during the White House conversations.

He pointed out that the bishops' conference nearly a year ago adopted a policy statement favoring a new treaty. "Once a policy is adopted," he explained in a press briefing, "it is followed up."

The churchman said he also commended the President on the administration's opposition to federal funding for abortion, and reiterated the Catholic Church's support for a constitutional amendment outlawing abortions.

The White House meeting of the two bishops was the first meeting of President Carter with member of the hierarchy since he became President.

During last year's election campaign, Archbishop Bernardin and other top officers of the hierarchy met with both presidential candidates to discuss abortion and other campaign issues.

In their White House meeting this week, at which Vice President Mandal also was present, the Catholic bishops registered concern for such issues as undocumented aliena, unemployment and welfare reform, the archbishop said.