Victims of the 2011 floods in south-east Queensland did not try hard enough to take their belongings to higher ground, dam operator Seqwater will argue in a large class action in the Supreme Court of New South Wales.

Lawyers acting for 6,000 people seeking compensation in the wake of the deadly flood disaster have told day four of court hearings they will vigorously defend claimants against accusations of "contributory negligence" being levelled by the Wivenhoe Dam operator.

Lawyers acting for 6000 claimants say they will vigorously defend accusations of 'contributory negligence'. ( Aimee: User submitted )

The class action against Seqwater, Sunwater and the State of Queensland alleges the dam operators failed to follow their own manual and did not make enough room for heavy rainfall until it was too late, heightening flood levels and damaging more properties.

Barrister for the plaintiffs Nicholas Owens SC told the court Seqwater wanted to transfer some of the blame to victims.

In court on Thursday, Mr Owens shared the story of victims Maria and Vince Rodriguez, who had owned a store Sportspower which was destroyed when Fairfield Gardens Shopping Centre flooded on January 11, 2011.

The court heard that on that morning, the Rodriguez couple was told to close the store because the centre was at risk of flooding.

The pair shut up shop and went to save their own home, where they put as many of their possessions as they could into three cars before going to spend the night at a friend's house.

"It wasn't just their business that was threatened, it was their home too," Mr Owens said.

He said when the couple went to check on the store early the next morning they found the shopping centre carpark already underwater, so they filled their cars with the most expensive stock and moved it to their son's apartment.

By 11:30am there was a metre of water inside the shop and 3 metres of water inside their home.

Mr Owens told the court the couple lost $100,000 of stock and the shopping centre was closed until May 2011.

"There were up to 15 people working long hours for three days to clean up the damage," he said.

"That extended period of closure had an adverse impact on their business and it never fully recovered."

It closed in 2015.

Previous floods an indicator

Mr Owens said Seqwater maintained the couple should have known the land was at risk of inundation because it went under in the previous devastating floods of 1974.

Children clear mud from the front steps of their flooded home in Fairfield, Brisbane, January 15, 2011. ( Tim Leslie: ABC )

"That is said to have been negligent because the land upon which the Fairfield Gardens Shopping Centre was built had flooded in 1974, a point in time I should point out Mr Rodriguez and his wife were living in El Salvador," Mr Owens said.

"Remember too of course that 1974 was before Wivenhoe Dam was built and as we know the substantial purpose of Wivenhoe Dam was to protect Brisbane from floods."

Mr Owens said another claimant, Fernvale homeowner Lynette Lynch, was also told by Seqwater she was negligent because her property had flooded in 1893 and 1974, before Wivenhoe Dam was built.

The court heard Ms Lynch had no warnings from authorities about flooding and her home was so badly damaged it had to be rebuilt.

Lawyers will argue the claimants could not have known the extent of the flood that was to come and made every effort to save their belongings.

Seqwater and Sunwater are yet to introduce their defence to the court, but in a statement issued earlier this week Seqwater said it was sure the court would find its actions reduced the severity of the flood.