The Equality Authority has been granted the right to appear as a "friend of the court" in a case for the first time.
The case concerns a Traveller family who are challenging the trespass legislation used to remove Travellers from land, usually that owned by local authorities.
The legislation is being challenged on the basis that it fails to take account of the accommodation needs of the Traveller family, and that it disproportionately affects Travellers.
The Laurence family is challenging the Criminal Justice (Public Order Act) on the basis that it has a discriminatory impact on Traveller families. It permits An Garda Síochána to arrest people for being on specified land and to remove caravans.
The family is bringing High Court proceedings against Ballina Town Council, Mayo County Council, the Commissioner of An Garda Síochána, the Director of Public Prosecutions, the District Justice sitting in Ballina, and Ireland and the Attorney General.
Mr Justice Iarfhlaith O'Neill allowed the Equality Authority the right to appear in the case as "amicus curiae" or friend of the court, to give evidence in relation to the EU Race Directive.
This directive, which applies in Ireland, prohibits discrimination based on racial or ethnic origin in a range of areas, including housing.
Niall Crowley, chief executive of the Equality Authority, welcomed the decision, adding: "Should the race directive arise in the case it will provide an important opportunity to set out its relevance.
"This presents a valuable precedent in our work of combating discrimination and promoting equality of opportunity."