Key US lawmakers urged caution in any efforts to include Japan in a future trans-Pacific agreement, questioning whether the accord would pry open the country's historically closed markets.
"Japan has long sheltered its domestic market from meaningful competition," the top Republican and Democratic members of the House and Senate committees in charge of trade issues wrote to US Trade Representative Ron Kirk.
US negotiators must asses "whether Japan is willing and able to meet the high standard commitments inherent in US free trade agreements and whether inclusion would truly open this historically closed market to the benefit of our companies, workers and farmers," they said.
Japan is debating whether to join the Trans-Pacific Partnership (TPP), a trade pact being negotiated by nine nations including the United States, but the government faces strong opposition from farmers.
"Autos, various agriculture products including beef, insurance, drugs and medical devices as well as a large number of other US goods and services face serious market access barriers in Japan," the lawmakers wrote.
"Many of these barriers are deeply embedded in Japan's economy, and to date, have persisted notwithstanding existing trade rules and years of bilateral engagement," they said.
The lawmakers hoped that new rules under TPP would be "sufficiently robust" to remedy "at least some of these concerns," but warned that Japan's inclusion "would add dramatically new dimensions and complexities" to the talks.
Senate Finance Committee Chairman Max Baucus, a Democrat, and ranking Republican Charles Grassley, as well as House Ways and Means Chairman Dave Camp, a Republican, and ranking Democrat Sander Levin signed the letter.