More than 70 per cent of applications for redress for survivors of sexual abuse have named more than one institution where they experienced abuse.
Of the almost 6000 applicants, more than 1800 people, or about 30 per cent of applications have named four or more institutions where they experienced child sexual abuse, a parliamentary inquiry has heard.
That figure is "devastating," Department of Social Services officials said, and the high number of cases with multiple institutions had increased the complexity of processing applications leading to blow outs in waiting times.
Twenty-three people had died while waiting for their redress payment, officials said.
While 116 organisations have joined the scheme, more than 540 applications have been stalled because the organisations named are yet to sign up.
While dozens are in the process of joining up or communicating with the department about joining, nine institutions with applications from child sex abuse survivors have refused to join up the scheme.
The nine institutions are among 284 non-government institutions that have not joined and are therefore stalling more than 540 applications made to them by abuse victims.
More than 40 of the institutions are now defunct.
About 280 of the applications being held up are linked to just 15 institutions.
But senior officials from the Department of Social Services wouldn't say who the nine organisations were.
"Unfortunately because of the nature of the legislation, that is protected information," the department's deputy secretary Liz Hefren-Webb told a parliamentary committee in Canberra on Wednesday.
The department officials said they were working "very closely" with the institutions that have not joined and expected more to sign up before the June 30 deadline.
The committee is looking into how the redress scheme is being implemented and will travel across the country over the next few months to hold public hearings.
The government has named institutions, such as Jehovah's Witnesses and Football NSW, that were identified in the Royal Commission into Institutional Responses to Child Sexual Abuse that have not signed up to the scheme.
As of mid-February, payments had been made to more than 1100 abuse survivors.
About 25 per cent of applications are from indigenous Australians, the officials said.
The scheme can offer counselling, a direct response from responsible institutions and a redress payment.
- with AAP