Other companies in the five worst brands in Australia were Telstra, NewsCorp and Amazon indicating that the media and telecommunications sector have work to do. News Corp publishes The Courier-Mail along with The Australian, The Daily Telegraph, the Herald Sun and The Advertiser in Adelaide. It also owns Sky News in Australia.

The details of an estimated 10 million people were leaked in the Optus data breach last year and a class action was also underway against the telco.

Roy Morgan said the data breach resulted in “the immediate and sharp increase in distrust for the brand” and the monthly levels of distrust were far higher than they were before the breach.

Roy Morgan chief executive Michelle Levine said once distrust takes hold it was very difficult to curtail.

The telecommunications sector was also considered to be the least trusted in Australia.

Levine said that while companies may see incremental improvements in trust, the residual distrust “does not just vanish”.

“Roy Morgan’s ongoing research on trust and distrust over many years has shown that while events become less top-of-mind due to new distrust-generating events, it would be remiss to believe that this means a brand has become trusted again,” she said.

“Distrust makes a brand fragile and is a powerful driver in the decisions which consumers make.

“Brands need to be aware of the ongoing dangers that distrust presents with lingering distrust a significant risk.”

Data breaches have become a global problem for business and a recent study found they had increased in the second quarter of 2023, with more than 110 million accounts leaked around the world.

Australia was among the 10 most-breached countries for the quarter.