The Nine Network has lost its bid to reduce a $3.6 million damages payout to a wealthy Queensland family defamed in a report about the fatal Grantham floods in 2011.

Toowoomba’s Wagner brothers were defamed by a 60 Minutes report from May 2015 that incorrectly insinuated they were responsible for the destruction of the town and deaths of 12 people.

They argued the report insinuated the collapse of a wall at a Lockyer Valley quarry they owned caused the “man-made catastrophe”.

The report, entitled “The Missing Hour”, described the wall of water that fatally swept through Grantham as an “inland tsunami”.

The report did not expressly blame the four Wagner brothers for the deaths, but the family believes it led people to believe they caused the disaster, sought to cover it up and refused to answer to the public.

Nine’s lawyer, Sandy Dawson SC, argued Justice Peter Applegarth erred when he calculated the payout to the brothers and his client should pay a much lower figure.

He said the judge had treated the 60 Minutes broadcast and journalist Nicholas Cater’s words as two different publications of the same defamatory material.

The Wagner family’s lawyer, Tom Blackburn SC, argued that the defamation in the 60 Minutes broadcast and that caused by Mr Cater’s words were “very different”.

The program was filled with “eerie” music and was relentlessly accusatory in tone, he said.

It also contained references to the deaths of 12 people and included the words “incomprehensible grief, trauma, and devastation” while insinuating concerns about the quarry had been hidden from the public.

In a decision handed down on Tuesday, the Court of Appeal determined the Justice Applegarth made “appropriate orders” and declined to reassess the payout amount.

-AAP