The Dublin Airport Authority has extended the suspension of flights until 5am tomorrow morning due to heavy snowfall.

A statement from the DAA tonight said:

'Flight operations were suspended at Dublin Airport from 18.30 as a result of heavy snowfalls. Snow continued to fall persistently for the following three hours.

'Our snow and ice crew are working to clear the runway, taxiway and apron area in time for the first wave of flight arrival and departures tomorrow morning - subject to favourable weather conditions.

'Passengers planning to travel tomorrow are advised to contact their airline or airline's website BEFORE coming to the airport.

'With over 600 acres of runway, taxiway and apron area to clear one inch of snow over the airfield equates to more than 15,000 tons of snow to be removed.'

When the flights were suspended this evening, Siobhan Moore of the DAA said that friction tests showed that the braking action of aircraft had been compromised following snow showers this afternoon.

270 flights and approximately 40,000 passengers have been affected by the closures at the airport today.

Aer Lingus had earlier cancelled all its flights out of the airport for the rest of the evening.

The airline said this morning's three-hour delay had a knock-on effect on its operations.

Flights had resumed at the airport at 1pm after being suspended this morning because of heavy snowfalls.

The earlier stoppage caused the cancellation of around 100 flights, which affected almost 15,000 passengers.

Ryanair said it could not understand the need to close the airport for such a long period.

The airline said it believed the main runway at Dublin could be cleared in less than one hour and it called on the Government to investigate the closures.

The DAA said it thought the closure was necessary and it was surprised and disappointed with Ryanair's comments.

Other Irish airports have remained fully operational throughout the day.

European airports are still working to deal with the backlog of thousands of passengers trying to make their way home for Christmas.

Severe weather warning

Met Éireann issued a new severe weather warning tonight.

Forecasters said snow showers would continue for a time in eastern counties of Leinster, giving further accumulations of two to five centimetres locally.

There will be widespread air and ground frost too, while freezing fog inland will reduce visability to below 100m in places.

Dangerous road conditions

Driving conditions remain difficult in many parts of the country, with conditions desribed as treacherous in some parts.

The worst affected routes include the M7 Dublin to Limerick road southbound in Dublin and Kildare, and the M1 in both directions near the services area at Balbriggan, Co Dublin.

The Department of Transport and the Severe Weather Co-ordination Service said that all of the major inter-city routes and local primary routes are being treated and maintained for the severe weather.

Motorists are again being warned to exercise caution on the roads.

Temperatures plummeted to -15C in some areas overnight and compacted ice and snow have made driving conditions hazardous.

The National Roads Authority has said there is enough salt to treat national primary roads over Christmas following the arrival of another shipment into the Port of Cork this morning.

The severe weather is continuing to affect other transport services across the country.

Dublin Bus services are still experiencing delays and disruptions and Bus Éireann is operating most services, although some in the northeast have been cancelled.

Dublin Bus has said it will not operate its Nitelink service tonight due to road conditions in the capital.

Bus Éireann will provide intercity services on Christmas Day between Dublin, Dublin Airport and several major towns and cities.

These include Limerick, Belfast, Cork, Galway, Rosslare, Ballina, Sligo, Waterford, Letterkenny, Donegal, Clonmel, and Derry.

Motorists are being advised to avoid unnecessary journeys, if travelling allow plenty of extra time and leave plenty of distance between vehicles.

With flights into Dublin affected again, many people are turning to other options and Irish Ferries says many of its services are fully booked, but there are spaces available for foot passengers.

The company says it expects to carry all passengers who present themselves to travel between now and Christmas Eve.

The ESB has warned people not to walk or skate on frozen water at its reservoirs at Ardnacrusha, Poulaphouca, Iniscarra and Carrigadrohid, as well as lakes and the River Shannon on which it says ice is very thin.