A total of 923 former Hansen's disease patients filed a lawsuit against the state Monday, demanding it pay them 115 million yen each in compensation for forcing them into isolation to undergo treatment for the disease.

The suit brings the number of plaintiffs suing the state at district courts in Kumamoto, Okayama and Tokyo in connection with the case to about 1,700, which accounts for about 40 percent of those still living in state-run sanitariums built decades ago, lawyers said.

The move is apparently in protest over the government's plan to seek an out-of-court settlement after appealing a May 11 ruling by the Kumamoto District Court ordering the state to pay compensation to former Hansen's disease patients, the lawyers said.