Japan has made a major new proposal on a knotty issue of public works construction in an effort to blunt congressionally ordered trade sanctions, Reagan administration officials said yesterday.

The proposal, submitted late Monday by Japanese Ambassador Nobuo Matsunaga on the eve of Prime Minister Noboru Takeshita's arrival here for his first official visit, was aimed at settling a major dispute over Japanese barriers to the participation of U.S. construction and engineering companies in an estimated $60 billion in public works projects over the next decade.

A senior administration official, briefing reporters at the White House on the Takeshita visit, said "we hope and expect" that the plan will meet congressional requirements that U.S. companies have the same access to Japanese public works projects that Japanese companies have in this country.

But other administration officials were less optimistic about the sweeping nature of the Japanese proposal, one calling it "so amorphous as to consist of not much more than a willingness to negotiate on including all public works projects" in an agreement to break down Japanese barriers to U.S. companies.

U.S. officials want to extend an agreement that provides equal access for U.S. companies to the $8 billion Kansai International Airport in Osaka and a new Tokyo Bay bridge project to all public works construction projects, a commitment that former prime minister Yasuhiro Nakasone agreed to last year.

Administration officials said Japan backed down from that commitment under strong pressure from the politically powerful construction industry. Takeshita has even closer ties than Nakasone to that industry, but he is believed to be more skillful than Nakasone in building the consensus necessary in Japan to make decisions.

Sen. Frank H. Murkowski (R-Alaska), who placed the sanctions proposal in the massive funding bill passed by Congress and signed into law by President Reagan last month, said the proposal "will do nothing to get Japan off the {sanctions} list."

A Japanese Embassy spokesman said the proposal would create a "designated competitive bidding system" to regulate the competition for large public works projects in the future. Among other things, the special system would involve a formula for getting around a requirement that foreign companies have a record of construction experience in Japan before they can compete for public works contracts.

Secretary of State George P. Shultz and Japanese Foreign Minister Sosuke Uno conferred on the construction proposal and a variety of other issues yesterday morning, several hours before Takeshita's midday arrival.

Japan appeared to signal a willingness to settle its agricultural trade disputes with the United States. A Japanese spokesman said Uno told Schultz that Japan will "properly settle" the issue of its barriers to farm imports in 10 categories that were found by an impartial panel to have violated international trade laws.

Administration sources said the settlement will be announced next month at a meeting of the international compact that regulates world trade, the General Agreement on Tariffs and Trade.