The Japan Medical Association, one of the most powerful supporters of Prime Minister Junichiro Koizumi's Liberal Democratic Party, has turned against the LDP over its plan to require salaried workers to pay more in outpatient fees and intends to try to topple the government.

"We are not seeking political upheaval, but that could be possible," Takaaki Ishikawa, vice president of the association, warned at a joint news conference Thursday with leaders of the associations of dentists, pharmacists and nurses.

The medical association has urged the government and the LDP to freeze a planned 50 percent increase in the fees that salaried workers pay for outpatient medical treatment starting in April, fearing there will be a drop in patients.