By Denise O'Donoghue and Catherine Shanahan
Update 9.50am: Flights have resumed at Dublin Airport following a reported issue with the air traffic control radar system.
The airport says the issue has been resolved by the Irish Aviation Authority.
Knock on delays are expected following the disruption caused by the system outage.
Earlier: Radar system failure leads to flight cancellations at Dublin Airport
Update 9.27am: All flights are temporarily cancelled at Dublin Airport following the failure of the radar system.
"An issue with the IAA radar system at Dublin Airport means that flight operations have had to be temporarily suspended."
A zero-flow rate is understood to have been implemented in the airspace.
One passenger, who does not wish to be named, contacted us to say he and other passengers are sitting on a plane in Dublin Airport but their flight has been delayed.
"Right now I’m sitting on a plane," he said.
"Dublin Airport planes are grounded due to radar system failure, this is the second time Irish airspace affected in so many months.
"We have been advised by the captain that there may further delays, currently our flight is 35 minutes late."
A similar occurance happened in October when a software problem at Shannon Air Traffic Control (ATC) centre forced the closure of Irish airspace.
Air traffic controllers in Shannon were forced to introduce a zero flow rate on October 2, allowing no aircraft to enter Irish airspace for a number of hours while frantic efforts got underway to organise re-routing of hundreds of aircraft due to fly through Irish airspace en route from the US to Europe.
An irregular software issue was said to be to blame at that time.
The IAA’s Area Control Centre in Shannon handles over 90% of all air traffic on the North Atlantic. This equates to approximately 1,400-1,500 aircraft every 24 hours during the busy summer months, according to its website.
In 2017, Shannon Air Traffic Control safely handled over 343,000 flights.
It is unknown if other Irish airports are affected by today's radar failure.