Lawyers for the victims say the first suits will be filed in late March by a group of some 20 people who are seeking compensation of between $139 million and $555 million each, Kyodo News reported Monday.

Other groups are expected to follow in April, filing their cases in 11 district courts across Japan, the lawyers say.

Last month the Diet enacted relief measures for people who contracted hepatitis C from tainted blood products after Japan's Supreme Court ordered compensation for five hepatitis B victims, Kyodo said.

Japan no longer mandates vaccinations against certain diseases due to side effects that prompted a number of lawsuits.