An application to significantly expand Galway Harbour is being considered by the Ministers for Housing and Culture.
It is the latest stage in a long-running effort to secure permission for the proposed €126 million project.
It would involve the reclamation of 27 hectares from the seabed, and extensive development, to enhance and expand the port.
In 2015, An Bord Pleanála indicated that compensatory environmental protection measures would be needed, if the extension was to proceed.
The board said that certain elements of the proposals would have a "significant adverse impact" on the integrity of Galway Bay, a special area of conservation (SAC).
After proposed compensatory measures to offset any damage were set out, the plan was referred to Europe for approval, under a rarely used derogation of the Habitats Directive.
Under Article 6(4) of that legislation, submissions can be made if a project is necessary for 'Imperative Reasons of Overriding Public Interest’ (IROPI).
The European Commission responded to that submission in recent months and the matter was referred to the Minister for Housing by An Bord Pleanála.
This evening, the department confirmed that Minister Darragh O’Brien wrote to Minister for Culture Catherine Martin on 27 April to request her views as to whether the compensatory measures would be sufficient to ensure the integrity of the SAC.
There is no time frame for a decision in this regard.
Confirmation of the ongoing deliberations came as Galway Harbour Company announced plans for a redevelopment of the part of the existing port, closest to the city.
The company said the plans are largely contingent on approval for the extension to the harbour.