Alan Jones' Brisbane defamation trial is set to enter its final days as both sides deliver their closing arguments.
John, Denis, Neill and Joe Wagner are seeking $4.8 million in damages from the radio broadcaster, Harbour Radio, 4BC and journalist Nick Cater over 32 broadcasts in 2014 and 2015.
The brothers claim they were accused on-air of the deaths of 12 people in the town of Grantham during the 2011 Queensland floods, when one of the walls of the Lockyer Valley quarry they owned collapsed.
They allege they were also subjected to abuse, including accusations of a high-level cover-up, corruption and intimidation relating to their Wellcamp Airport.
Jones admitted during the trial his comments about the Wagner brothers were savage but said he and his team always took reasonable steps to be accurate.
He also gave evidence some of the claims he made were his honest opinions.
The final witnesses in the defamation trial gave evidence two weeks ago.
Justice Peter Flanagan then adjourned to give both sides time to prepare their closing arguments, which are expected to get under way on Wednesday.