Thousands of disgruntled passengers stranded at London's Heathrow Airport could spend several more days in limbo, after another day of cancelled flights.

After 12 centimetres of snow fell on parts of England, including Heathrow, over a five-hour period Saturday, officials at one of the world's busiest airports were still struggling to clear the airfield and get planes off the ground.

BAA, which operates Heathrow, said only one-third of scheduled flights will be able to land and take off at the airport until at least 6 a.m. local time Wednesday, meaning it could be well past Christmas before the backlog of passengers is cleared.

The British government approved night operations at Heathrow in order to get more passengers on their way. However, temperature fluctuations have made it difficult for crews to keep up with clearing ice around parked aircraft.

BAA said "every available" staff member has been called in to help restore operations at the airport.

But British officials said an inquiry is necessary into why the agency has failed to get Heathrow fully operational.

"It can't be beyond the wit of man surely to find the shovels, the diggers, the snowplows or whatever it takes to clear the snow out from under the planes, to get the planes moving and to have more than one runway going," said London Mayor Boris Johnson.

Thousands of passengers slept on the airport's floor Sunday night, while thousands more with boarding passes for Monday flights were denied entry.

Passengers have complained since the weekend that airline and airport staff offered little information as wait times stretched from hours into days.

"The whole situation is horrible," said Sophiya Bolkova, who has been trying to get home to Moscow since Saturday. "We are very angry. People were just mean, rude, sleeping on the floor, babies sleeping on the floor, no information, no help, no money for hotels."

Air Canada said it planned to operate three flights to Heathrow Monday evening, but two were cancelled.

Passengers at Heathrow trying to get to Canada for Christmas said they had little choice but to wait out the weather.

Mother Nature was also preventing passengers from leaving Britain by train, and Eurostar said rail travellers should postpone or cancel their trips to Belgium and France if possible.

Elsewhere in the United Kingdom, Edinburgh airport warned travellers of possible disruptions and Belfast International Airport said "severe weather" was hampering flights.

In the Republic of Ireland, Dublin airport was fully operational Monday, though passengers were told to consult with their airline before heading to the airport.

Meanwhile, the two biggest airports in Paris were ordered to reduce their flights by 30 per cent. French aviation spokesperson Eric Heraud said these reductions would help to deal with problems stemming from the slowdowns at other European airports.

In Brussels, airport staff told passengers via Twitter that there was a shortage of de-icing fluid that would delay some departures until at least midnight Tuesday.

While the runways were clear of snow and ice in Frankfurt, Germany, the airport cancelled 300 of its 1,340 flights because of problems at other airports.

With files from The Associated Press and The Canadian Press