Ryanair boss Michael O’Leary has launched a fresh broadside against Irish Transport Minister Eamon Ryan as he blamed a passenger cap at Dublin Airport for blocking the airline’s growth.

Mr O’Leary said Mr Ryan and his Green Party colleague Catherine Martin, the Minister for Tourism, are “dunces” who should leave politics if they do not act to remove the cap.

Ryanair said while it expects to grow traffic at Ireland’s regional airports in Cork, Shannon and Knock, it cannot expand in Dublin due to a limit of 32 million passengers per year.

The company said the cap limits its plan to grow its Irish traffic by 50% by 2030.

I can't imagine when I've ever been personally abusive. I've said he's incompetent. I don't think that's personally abusive, it's a statement of fact

The airline’s chief executive told a press conference on Thursday that Mr Ryan had failed to deliver on the National Aviation Policy of enhancing Ireland’s connectivity, fostering growth in aviation, and maximising the contribution of aviation to national development.

Mr O’Leary, one of Ireland’s wealthiest businessmen, posed for photos holding cut-outs of the two ministers wearing green dunce caps.

Mr Ryan has previously said the airline chief has become “personally abusive” in his comments.

Asked on Thursday if he feels the latest media stunt is abusive, Mr O’Leary said it is intended to be “humorous”.

He said: “I can’t imagine when I’ve ever been personally abusive. I’ve said he’s incompetent. I don’t think that’s personally abusive, it’s a statement of fact.

“I think calling him a dunce is fair, but if he’s that thin-skinned or that upset by personal abuse, I have two suggestions: One, do something useful and lift the cap. Or two, maybe politics isn’t for you, if you can’t handle the occasional barb from some loudmouth like me.”

Mr O’Leary said Ryanair will add 50 Boeing 737 aircraft this summer, open 80 new routes and grow overall traffic by more than 16 million to 200 million.

But he said none of the new traffic will be delivered at Dublin Airport due to the cap and will instead be in Spain, Italy, Poland, Morocco, Denmark and Albania.

He also criticised Dublin Airport operator DAA for plans to raise airport fees by 45% by 2026 when compared to 2022 levels.

The airline said the cap is an “indefensible” artificial restriction given that Dublin Airport had spent 300 million euro (£257 million) on opening a second runway which could provide capacity for 60 million passengers.

He said: “If Ireland had a capable Transport Minister committed to delivering our National Aviation Policy, then he or she would intervene to lift this cap while the planning matter is being dealt with, or better still, pass legislation to raise the traffic cap at Dublin Airport to 50 million passengers.

“Dublin Airport is a national asset. It is our main gateway on and off the island of Ireland. Its growth cannot be left to a few county councillors in Fingal or the usual planning nimbys and loonies who will block or delay this cap for up to four years.”

Mr O’Leary said Ryanair is making a 4 billion US dollar (3.7 billion euro, £3.2 billion) investment in Irish aviation by basing 40 aircraft in the country.

He said it is offering 210 routes, 10 of which are new options from the regional airports.

The chief executive said Ryanair would place four new aircraft in Dublin and implement 12 new routes to and from the airport this summer if the cap was not in place.

He added: “We would have increased frequencies on other routes and grown traffic in Dublin by about another two million passengers from last year’s number.”

Mr O’Leary said Dublin Airport is losing traffic to almost every other country in Europe.

“Ireland has a Green Transport Minister and a Green Tourism Minister,” he added. “After four years of failure, these two ministers have shown they are sadly not up to the job.

“If they don’t act now to abolish this traffic cap at Dublin Airport, then they should quit.

“The choice is simple. These two Green ministers should either grow or go.”

Asked if he is another rich businessman taking on an environmentally friendly agenda, Mr O’Leary said: “Nobody does more for climate change than Ryanair does.”

He said the airline is investing 20 billion euro (£17 billion) in aircraft which could carry 20% more passengers with 20% less fuel.

Mr O’Leary said he wants to hold a face-to-face meeting with Mr Ryan at the Ryanair offices in Swords next Thursday.

The Green Party declined to comment.