Brisbane Supreme Court Justice Peter Flanagan delivered the costs judgement into the high-profile defamation case on Friday, two months after he found Mr Jones repeatedly defamed Denis, John, Neill and Joe Wagner on-air over several months of broadcasts.

Mr Jones claimed the brothers were responsible for the deaths of 12 people in the 2011 Grantham floods when the wall of a quarry the brothers owned in the Lockyer Valley collapsed.

Over 30 broadcasts between October 2014 and August 2015, Mr Jones made defamatory claims that the family had covered up their "culpability" in the flood deaths and had lobbied Queensland Premier Anastasia Palaszczuk to avoid exposing the "truth".

The brothers sought $4.8 million in damages in a seven-week trial, which ultimately resulted in a $3.7 million payout from Mr Jones and the two radio stations.

Mr Jones was also restrained from speaking publicly about the case under court order, but said he felt he had "let down" the people of Lockyer Valley.

In total, Mr Jones and radio stations 2GB and 4BC were ordered to pay $938,746 in damages to each of the brothers.

4BC and 2GB are owned by Macquarie Media, which is majority owned by Fairfax Media.

However, the four Wagner brothers were ordered to pay the costs of journalist Nick Cater, who was originally named in the defamation case as a defendant.

Proceedings against Mr Cater were dismissed by Justice Flanagan.

Speaking after the trial in September, Denis Wagner on behalf of his brothers described the distress and hurt they had suffered during the attacks on their character by Mr Jones, saying the family decided to take a stand against the "spiteful" attacks.

Mr Jones is currently off-air after suffering severe back pain and was admitted to hospital for treatment.