Speaking in an interview with the Irish Examiner, Mr Donohoe said if traffic numbers through the airport during 2015 are replicated this year, then a third runway at Dublin will be required.
Focus on expansion of Dublin has come to the fore in the light of the ongoing debate in London over whether to build a third runway at Heathrow Airport or a second runway at Gatwick.
Mr Donohoe said there is fantastic potential for Dublin Airport to expand its operations and that the Dublin Airport Authority (DAA) will put forward the business case for expansion.
He said that if traffic numbers at Dublin Airport in 2015 were to continue, then there would be a need for a second parallel runway to the current main runway 10-28.
“If the demand for Dublin Airport that we saw in 2015 were to continue, there would be a need for a second parallel runway,” he said.
“Dublin Airport are at the end of a very successful year.
They themselves will have to make an analysis of what 2016 will look like to see if that rate of growth is sustainable.
“If it is sustainable, they will develop a proposal that will go to Government.”
Mr Donohoe said that should the long-term demand show itself to be sustainable, then he would back the development of a third runway at Dublin.
“But what I want to see first is to see are the growth figures sustainable,” he said.
“If our country is going to go ahead with the investment, we need to see first strong evidence that the demand is there.
“If the demand is there, then it is something I would support.”
The DAA already has planning permission for a second runway and the estimated cost of building a third runway is in the order of €250m.
“We believe that, due to predicted demand that’s now very likely to occur at Dublin Airport, there will be a need for a second parallel runway,” said Mr Donohoe.
An estimated 24m passengers used Dublin Airport in 2015.
A parallel runway at Dublin could be used at the same time as its current primary runway.
However, Mr Donohoe has already ruled out a second airport for the city.
“We have in Dublin Airport at the moment an airport that has made huge progress,” he said previously.
Mr Donohoe also said in the interview that he was very proud of being able to sell off the State’s 25% stake in the former national airline, Aer Lingus.
He said the takeover by IAG means the potential for Aer Lingus to expand is enormous.
“It was a massive deal for Aer Lingus. It is something I am very proud of as I believe it will secure the jobs in Aer Lingus,” he said.
“We are already seeing the added potential that the merger gives Aer Lingus.
“They launched three new transatlantic routes for 2016, employing 200 additional people.
“That is the kind of thing the IAG deal allows Aer Lingus do more of.
“Within all that, the negotiations had with Willie Walsh were extremely demanding. It was not easy, anything but easy.”