Issues of confidentiality, in relation to documents provided by the Special Liquidators and state institutions, are still plaguing the work of the Commission of Investigation into IBRC.
In his second interim report, Mr Justice Brian Cregan said legislative changes are needed if the Commission can proceed with its investigation into the Siteserv transaction, as well as others.
So far the Commission's work has not moved beyond the Siteserv transaction.
There are 38 transactions in total to be investigated.
The Commission was set up to investigate all transactions that resulted in a loss of at least €10m to the IBRC.
The write-off of IBRC loans in respect of Siteserv is greater than €100m, one of the six largest write-offs under investigation.
The report said that pending the resolution of the legal problems, which were identified in the first report, and in order to minimise the cost to the taxpayer, the Commission has not progressed investigation into any other transaction apart from Siteserv.
Because of the uncertainly the Commission is unable to estimate its future costs.
But the report said the Commission's costs and third party costs will be "very significant" if is required to investigate all 38 transactions.