“Further extending hours of service would by definition, reduce the amount of time available for maintenance work”
Currently the Luas does not operate between 1am and 5am.
Transport Minister Eamon Ryan had asked the authority in June to examine the prospect of running services on a 24-hour basis.
But the NTA has said that a significant extension of the tram system is "not something that should be progressed at this point.
In a statement to JOE.ie, an NTA spokesperson said the transport authority, along with Transport Infrastructure Ireland, had recently examined the prospect of the Luas operating past 1am.
However, they determined that essential maintenance on the tram system - such as on its overhead cable systems, overhead line equipment and rail works - can only be carried out when all trams are out of service.
"Even with the current schedule in place, the nightly window for that preventative maintenance work to take place is only somewhere between two and three hours," the NTA spokesperson said.
"Further extending hours of service would by definition, reduce the amount of time available for maintenance work, which could result in a diminution of services at other times of the week.
"The Friday-Saturday and Saturday-Sunday sets of engineering hours are particularly valuable on Luas, as the longer window due to the later start on Saturday and Sunday gives extra time for longer tasks, which again are required regularly.
"Were we to regularly run later services on Luas at say weekends, an alternative time would be required to complete these activities."
While the NTA has ruled out such a late night Luas service, the authority said that overnight bus services are being prioritised.
It pointed out that late night bus services have been introduced on a number of routes such as the 15, 39a and 41 in recent years.
A new 24-hour operation is in place between Sandymount and Adamstown via the city centre and South Lucan, and also between Ringsend depot and Maynooth/Celbridge via the city centre and Lucan Village.
An orbital route along the N4 between Blanchardstown and the Point Village via DCU and Collins Avenue has also been rolled out.
The NTA said further 24-hour services are expected to commence in late summer on routes G1/G2 to Liffey Valley/Red Cow via Ballyfermot, adding that future phases will include more expansion of overnight services.
The NTA argued that the delivery of 24-hour bus services on a regular schedule across the network “is more feasible”.
“The NTA is committed to delivering more of these services as the BusConnects Dublin network is rolled out,” they added.
However, Fine Gael TD Neale Richmond told The Journal that late-night Luas services are “badly needed” as are more 24-hour Dublin Bus services, “given the persisting issues with access to taxis in Dublin city centre”.
“This is becoming a public safety issue with many people being forced to walk home, often alone, late at night as public transport is not operating and taxis are hard to come by,” he said.