Cbus has resolved more than 6000 death and disability claims as the super giant's boss apologises to affected people and their families for the distress it has caused.
The Australian Securities and Investments Commission has taken the fund to the Federal Court over allegations it failed to pay more than 10,000 claims in less than 90 days.
It also alleged more than 6000 claims had been delayed more than 12 months by late 2022 - more than half the fund's claims at that time.
Cbus chief executive Kristian Fok told a parliamentary inquiry more than 6000 - about 80 per cent - of the 7500 claims subject to the legal action had been resolved.
These members and their beneficiaries had so far received $755 million in benefits, he said.
"I do want to again say sorry for the impact that the delays in processing of insurance claims have had on our members and their families," Mr Fok told the hearing on Thursday.
"We are committed to do better, and we will.
"Many of our members hold high-risk jobs where injuries and death are more common.
"We know that delays in processing claims can add to their distress at a difficult time."
Mr Fok said Cbus generally paid out on the insurance part of claims about 90 per cent of the time, much higher than the industry average.
"Many of the challenges we faced are not unique to our fund and they are system-wide," he said.
He said since being appointed chief executive of the fund in 2023 he had received strong support from the board to initiate "significant changes in our leadership and organisational capabilities" to improve outcomes for members.
The corporate regulator has said it will seek penalties, adverse publicity orders and compliance matter orders through court.
ASIC deputy chair Sarah Court accused the fund of failing its members at their most vulnerable.
She said ASIC was taking on the case to protect all other Australians trying to access the financial support they were entitled to.
Cbus, which is linked with unions including the CFMEU, manages $94 billion in assets, according to its website.