The Lindsay Tribunal could be halted in a dispute over papers which the Blood Bank insists are confidential.
The bank's claim has been backed by the tribunal.
The High Court has refused an application for a judicial review by the Irish Haemophilia Society as it wishes to hear first from the tribunal and the Blood Bank on Monday.
However, the IHS has been given permission to apply to halt the next phase of the tribunal, which is due to begin on Tuesday.
The tribunal is investigating how 220 haemophiliacs became infected with HIV and Hepatitis C through tainted blood products.