The government has unveiled its €27bn capital spending plan, which it says will create 45,000 construction jobs.
The plan includes a series of new road and schools programmes, as well as the construction of a new Metro North rail line.
This will also include a metro from Dublin city centre to the airport and Swords - the DAA has welcomed the decision.
"We have been highly supportive of the plans for a rail link from Dublin Airport to the city centre for many years and we're pleased that the Government has approved the new Metro North option," said DAA chief executive Kevin Toland.
"Dublin Airport plays an essential role in the Irish economy, supporting trade and tourism and a Metro link to the city centre will significantly improve the transport options for passengers," he added.
Last year, 36% of passengers used buses to access Dublin Airport, while 33% of passengers came by private car and 22% used taxi services.
But construction will not start until 2021, and will take five to six years to complete.
Transport Minister Paschal Donohoe says the cost of the revised project is significantly reduced.
Taoiseach Enda Kenny denies that the plan is a pre-election stunt, because there are plenty of things he wanted to include but could not.
The plan also includes:
- The Connolly to Maynooth line upgraded to full DART service
- The Phoenix Park Tunnel upgraded and opened to commuter trains in 2016
- The Cross City LUAS to Broombridge in Cabra to come on stream in 2017
- Significant funding for new and replacement buses, further upgrading of Quality Bus Corridors, and road maintenance
- An additional €100m available to fund the relocation of the remaining two Dublin maternity hospitals - the Coombe to St James’s, and the Rotunda to Blanchardstown
It will also see a €6bn investment in the road network - with money also provided for housing, health, education and flood defences.
Minister Donohoe says the funding will also allow for bus fleet replacement and capacity enhancement, upgrading of bus corridors and the completion of the Luas Cross-City project.
While additional funding over the final three years of the plan will see the new Metro North and DART expansion programme going ahead.
All in all, the capital plan will see €42bn spent, with State and semi-state companies spending a further €15bn.
Tánaiste Joan Burton says the plan will create tens of thousands of jobs.