Irish airspace was due to open this morning but it's reopening has been postponed until at least 1 pm today.
The postponement is due to the renewed eruption of the Icelandic volcano Eyjafjallajokull.
The Irish Aviation Authority (IAA) has said that Ireland is one of the core areas that will be affected by the volcanic ash cloud.
"There will be no commercial flights departing Ireland prior to 1p.m. An update will be provided mid morning but the restrictions may well be continued to a later time." said the IAA.
Shannon airport is to open at 1 p.m. local time, while Dublin may open at 7 p.m., while a decision will be taken during the day about Cork airport.
The Dublin Airport Authority (DAA) has asked all passengers to contact their airlines, and said that the air ban may extended.
Aer Lingus has been forced to cancel all flights today, the airline estimates that the canceling of flights will cost the company between $20million and $27million.
Some 45 percent of European flights will run as scheduled with up to 60 percent returning tomorrow.
Northern Europe is locked down until tomorrow afternoon.
Paris has reopened and the first flight since Thursday is expected today.
Regulators have stated that it may take several days for normal air traffic to resume in newly reopened airports.
Test flights carried out by several European airlines have found that the volcanic ash cloud's density has reduced significantly.
The ash cloud has led to the cancellation of over 60,000 flights.
EU transport ministers held a video conference yesterday and decided to gradually reopen European airspace.
They have divided Europe into open, closed and restricted zones.
Ireland's Meteorological office has said that the volcano is now emitting more lava than ash.
However recent eruptions have sent a cloud of ash 5km into the atmosphere.
They will reassess the situation in the evening.
The UK, Ireland, western Germany and the Benelux countries are the worst affected by the volcanic ash.
Ireland's Minister for Transport Noel Dempsey said he hoped in the coming days, that everything would return "as near to normality as possible."
Dempsey said that aircraft "won't be allowed up if there's any danger at all to passengers."
Tourism Ireland announced that it was losing 16,000 overseas visitors for each day airspace was closed.