Jones sparked 10,000 comments: court hears

One of the prominent Queensland brother suing Alan Jones for $4.8 million in defamation damages says he's had tens-of-thousands of comments and questions directed at him following the talkback radio host's on-air accusations.

Denis Wagner is giving evidence in Brisbane Supreme Court on Wednesday, where he and brothers John, Neill and Joe are taking action against Jones, Harbour Radio, 4BC and journalist Nick Cater over 32 broadcasts in 2014 and 2015.

Jones, the Wagners say, accused them of being responsible for 12 deaths at Grantham during the 2011 floods, when one of the walls of the Lockyer Valley quarry they owned collapsed.

They claim they were also subjected to constant abuse, including accusations of a high-level cover-up with politicians, corruption and intimidation.

In the years since Jones' comments were aired, Mr Wagner estimated he had been asked questions or received remarks about what was said about 10,000 times.

"They were intense and very consistent," he said.

"At least a few times a week, sometimes sort of daily, someone would ask or say something about it."

Mr Wagner said he had been stopped in the street in Brisbane, told "those Wagners guys ... are bad bastards" by a Sydney taxi driver who listened to Jones' show and grilled by a sales rep at a conference at Adelaide.

"This is sort of gut-wrenching stuff," he said.

"The feeling that you get is these comments that Alan Jones had made over such a extended period of time resonate with people."

They have decreased since the Wagners launched legal action, he said.

The judge-only trial is expected to run for about seven weeks.