Japanese Prime Minister Zenko Suzuki, under pressure from domestic political opponents, today rejected suggestions that his meeting last week with President Reagan had produced any significant new military commitments by Japan.

Anticipating sharp questioning in Japan's parliament, Suzuki said that the use of the word "alliance" in a statement he issued with Reagan did not have any military implications.

He also reiterated a determination to avoid any collective defense efforts despite an agreement with Reagan that Japan and the United States should establish an "appropriate division of roles" in the defense of Asian waters.

Suzuki's remarks contrasted with interpretations of the talk last week by U.S. officials, who said the summit had provided a general framework for negotiating increases in Japan's military responsibilities.

The Reagan administration has made it clear that it would like to see Japan relieve U.S. forces of air and sea patrols in a large part of the Western Pacific, and officials said they intended to discuss concrete proposals in a mid-June meeting of the two countries' military experts.

The communique issued by Reagan and Suzuki pledged Japan to "even greater efforts for improving its defense capabilities," and spoke of an "alliance between the United States and Japan [that] is built upon their shared values of democracy and liberty." Suzuki told reporters in Washington that Japan would provide limited patrolling of commercial sea lanes in the Western Pacific, and the joint statement pledged Japan to picking up more of the cost of stationing U.S. troops in Japan.

Suzuki's comments today were made in a report to parliament on the summit meeting -- which leftist politicians here have tried to depict as signifying a hawkish turn for the government's policy on defense -- and were obviously intended to reassure parliament that nothing had changed.

Whether Suzuki's remarks in Washington and the joint communique amount to any new commitment will not be known until the meetings between U.S. and Japanese defense officials begin this month in Honolulu.

But the prime minister told the parliament today that defense preparations will be made with consideration for Japan's financial situation and the flow of public opinion.

Both of those factors would be considered when weighing any new departures in the military field. Japan's Ministry of Finance has made it clear it will not permit any major increase in defense expenditures for budgetary reasons, and public opinion is opposed to new military adventures.

Opposition members of parliament have sharply criticized the wording of Suzuki's speech and joint statement, insisting that they point in the direction of Japan's remilitarization.

They have seized on the use of the word "alliance" in the joint communique as signifying an intent to move Japan into some form of military agreement with the Reagan administration.

Some elements of the Tokyo press also have been critical. In a sharply worded editorial, the Asahi newspaper declared that the "U.S.-Japan relationship has taken a great step toward becoming one of military cooperation" and called the Washington summit a turning point in postwar history.

Suzuki today rejected those interpretations. He defined the word "alliance" as having no military implications and said it merely referred to the common values of a free economy and democratic government shared by Japan and the U.S.

The Reagan-Suzuki communique also had referred to a "division of roles" between the two countries, wording that the antigovernment critics here have taken to mean a move by Japan toward military cooperation.

Suzuki emphasized today that, under its postwar constitution, Japan cannot enter into collective defense agreements. He stressed that Japan's role in Asia is to emphasize social and economic progress, not military measures. He also said that Reagan had "showed an understanding" that Japan's defense preparations must take place within the limits of the constitution, which nominally prohibits any military preparations whatsoever.

Foreign Minister Masayoshi Ito also tried to persuade leaders today that nothing had been changed by Suzuki's Washington visit, and invoked the name of the late prime minister Masayoshi Ohira to prove it. He said that during two visits to Washington, Ohira had used the word "alliance" to describe the U.S.-Japanese relationship.