Japan's embattled prime minister Shigeru Ishiba, fresh off a crushing defeat in upper house elections over the weekend, will not be in a position of strength to negotiate a favorable trade deal with the U.S., analysts said.

Japan's ruling coalition has lost its majority in the country's upper house, but Prime Minister Shigeru Ishiba has said he has no plans to quit.

The LDP and Komeito, its coalition partner, are expected to seek co-operation with other parties on a policy-by-policy basis, a strategy that could prove a recipe for instability.