Members of the Defence Forces could be drafted in to help with security at Dublin Airport.
They will undergo training to help alleviate some of the pressure on staff until the end of the summer if needed.
The Department of Foreign Affairs said the Dublin government has supported a request from the Minister for Transport Eamon Ryan.
The capital's airport, run by DAA, made international headlines in May after passenger queues stretched outside the terminals and more than 1,000 people missed their flights.
In a statement, Defence Minister Simon Coveney said: "While I recognise that the role of the Defence Forces is not normally to assist in the provision of services for a commercial airport, I have agreed to this request on a clear assurance that this is a distinct piece of work, provided in extreme circumstances, as a short-term emergency-related contingency action and is in direct response to a letter from DAA management to the Minister for Transport.
"The request is clearly defined in terms of the role and timeline, lasting no more than six weeks, in non-public-facing duties.
"Over the last number of days, I consulted with the Chief of Staff, Lieutenant General Sean Clancy on this request.
"Members of our Defence Forces will undergo an immediate period of training and stand ready to assist if the need arises.
"However, this support will be stood down in August when the busy holiday period has passed.
"The DAA have given assurances that they will continue with their own recruitment and onboarding of additional security staff and the introduction of other mitigations during this period."
In a statement, a spokesman for DAA said that 93% of all passengers spent 45 minutes or less queuing at Dublin Airport's security screening areas in the first three weeks of June.
"Some 77% of passengers queued for 30 minutes or less. Over the past weekend - which was the busiest Dublin Airport has experienced since the start of the Covid-19 pandemic - 91% of the 50,000 to 55,000 passengers that departed Dublin Airport each day cleared security screening in less than 45 minutes.
"While capacity reductions, which have been deployed at other UK and European airports, have been considered as a possible option, there is general agreement that this is undesirable, given that it would be very challenging to implement with airlines and it would have a material impact on the summer travel plans of a significant number of Irish passengers and families, most of whom have not enjoyed a foreign holiday in over two years.
"Hence, data outlined to government that a prudent contingency at this juncture could be for the State authorities and DAA to take initial steps to facilitate the training of Defence Forces personnel at the airport's vehicle control posts, should this ultimately be required.
"As a first phase, we outlined that the State could take preparatory steps in the immediate term to train and prepare Defence Forces personnel for such a deployment, in the event that significant Covid-19-related absences due to illness and infection affected DAA's own security team.
"Any deployment of Defence Forces personnel would only be triggered as a second phase, and only if ultimately required due to a Covid-19 outbreak.
"As recently as last weekend we have started to see the impact of the current rise in Covid-19 cases in the aviation sector, with 13 flights cancelled by one carrier last Sunday alone, citing an outbreak of Covid-19 amongst its staff as a key contributory factor."
In a statement, Mr Ryan said: "I would like to thank the Minister for Defence for his agreement to this request and I would like to thank the Defence Forces for their assistance in this matter.
"This is a contingency measure only and the deployment of the Defence Forces may not be necessary.
"I expect that the DAA will continue to manage through the summer period with passengers who heed the relevant advice making their flights and the majority of passengers passing through security in less than 45 minutes.
"As this is a contingency measure, the Defence Forces will only be deployed, if requested by the DAA, and in a scenario where there is a significant deterioration in passenger queuing times with a risk of large numbers of passengers missing their flights."
