The 2011 flood victims planning to sue the State Government and dam operators say justice is more important than compensation.
Hundreds of people last night packed into a hotel at Ipswich, west of Brisbane, to hear from law firm Maurice Blackburn about its planned class action.
International litigation funder Bentham-IMF recently committed to financing the suit.
Maurice Blackburn principal Damian Scattini says he expects that will make more people join the 5,000 who have already registered for the class action.
"I think a lot of people have been waiting, frankly, to have the announcement that the matter is definitely going ahead," he said.
Flood victim Kym Kitchener says she has joined because she wants people to be held responsible for the floods.
"Things that could have and should have been done, weren't," she said.
Maurice Blackburn has given people until the end of February to register, before they file the lawsuit.
Ipswich resident Des Cave says he has signed up because he believes the release of dam water was mismanaged.
"Money's not a big thing," he said.
"I just want to see that it is managed properly and that further down the track the situation doesn't happen again to the people.
"I know flooding is one of those things that happens, but it can be managed a bit better than it was."
© ABC 2013
12:37 EST A deep low pressure trough created a light show for residents and visitors alike about northern parts of New South Wales, with some areas picking up daily rain not seen since April.