Australia's government-mandated copyright collection agency has been diverting payments intended for journalists and authors to a $15 million "future fund" to fight changes to the law.

The Copyright Agency is the only body authorised to collect copyright fees from schools and universities on behalf of authors, illustrators, artists, photographers and publishers whose work is copied.

It has been criticised in a Productivity Commission review that is before the government over the transparency of its accounts and its practice of retaining, rather than returning, millions of dollars collected from schools and universities on behalf of the owners of "orphan works" who can't be traced.

It has traditionally hung on to that money for four years before distributing it to its members, attracting the ire of the commission, which wants it returned to the schools and universities from which it was taken.