Eleven flights to Malta have been cancelled so far today as flight cancellations continue across Northern Europe because of a cloud of invisible ash from a volcano in Iceland.

Flights due to arrive in Malta from Heathrow, Gatwick, Manchester and Birmingham in the UK have been cancelled, along with flights from Brussels, Moscow and Amsterdam, creating a nightmare to thousands of stranded passengers in Malta and abroad.

In Malta, hundreds of passengers turned up at MIA yesterday only to find out that their flight had been cancelled.

Air Malta had planned to put on extra flights to UK airports today, but their operation is uncertain because the UK authorities have said they expect British airspace to remain closed well into the evening.

Some 13 flights to Malta were affected yesterday as airspace was closed over Belgium, Finland, the Netherlands, Norway, Denmark and parts of Germany.

Meanwhile, AFP reports that experts have warned the fallout from the Eyjafjallajokull volcano in southeast Iceland, could take several days to clear.

And with thousands stranded in airports around the world, the European air traffic control group Eurocontrol said planes could stay grounded for at least 48 hours.

It estimated that 5,000 to 6,000 flights were cancelled yesterday as grey ash from the second major eruption in Iceland in less than a month blew across the north Atlantic, closing major airports more than 2,100 kilometres (1,300 miles) away.

Eurocontrol predicted that at least half of the 600 daily flights between Europe and North America would be cancelled today.

Belgium, Britain, Denmark, the Netherlands, Norway and Sweden shut down their airspace because the ash threatened jet engines and visibility.

Finland, France, Germany, Portugal and Spain also experienced major disruption.

The cloud spread over northern Poland late last night, threatening to disrupt attendance at this weekend's memorial and funeral services for President Lech Kaczynski, who was killed in a plane crash, which will be held tomorrow.

As Polish aviation authorities closed airspace over the north of the country, US President Barack Obama and other world leaders were monitoring the cloud before confirming their attendance at the ceremonies.

The National Air Traffic Services, which manages British airspace, said the cloud was moving south and grounded all non-emergency flights.

Saudi Crown Prince Sultan bin Abdul Aziz ordered hotel rooms to be provided to Saudi travellers stranded in Britain by flight ban.

In Scotland, health officials warned that ash falling to the ground over northern Britain might cause symptoms such as itchy eyes or a sore throat.

Belgian and Norwegian authorities said their airspace would remain closed most of Friday and that the outlook was not optimistic for the two subsequent days.

Flights headed for Europe were grounded all around the world. Norwegian Prime Minister Jens Stoltenberg was stranded in New York, the NTB news agency reported.

Amsterdam's Schiphol airport prepared beds and meals for stranded travellers. Hundreds spent the night at the Brussels airport and others across northern Europe.

The prevailing winds, however, allowed Icelandic airports to remain open.

The ash drifted at an altitude of about 8.0-10 kilometers (5.0-6.0 miles). Although it could not been seen from the ground, experts said it posed a major threat.

In the past 20 years, there have been 80 recorded encounters between aircraft and volcanic clouds, causing the near-loss of two Boeing 747s with almost 500 people on board and damage to 20 other planes, experts said.

The volcano on the Eyjafjallajokull glacier in southern Iceland erupted just after midnight on Wednesday.

Smoke from the top crater stacked more than 6,000 metres (20,000 feet) into the sky, meteorologists said. A 500-metre fissure appeared at the top of the crater on Wednesday, Iceland's RUV broadcaster reported.

The heat melted the surrounding glacier, causing major flooding that forced the evacuation of about 800 people.

"We have two heavy floods coming out from the melting of the Eyjafjallajokull glacier," police spokesman Roegnvaldur Olafsson told AFP.

The eruption -- in a remote area about 125 kilometres (75 miles) east of Reykjavik -- was bigger than the blast at the nearby Fimmvorduhals volcano last month.

"It is very variable how long these eruptions last. Anywhere from a few days to over a year," said geophysics professor and civil protection advisor Magnus Tumi Gudmundsson.

"Judging from the intensity of this one, it could last a long time."

He noted there were more than 250 metres of thick ice on top of the crater that quickly melted and caused massive flooding.

Last month, the first volcano eruption at the Eyjafjallajokull glacier since 1823 -- and Iceland's first since 2004 -- briefly forced 600 people from their homes in the same area.

That eruption at the Fimmvorduhals volcano only ended on Tuesday, hours before the new one sent up the cloud.

Sign up to our free newsletters

Get the best updates straight to your inbox:
Please select at least one mailing list.

You can unsubscribe at any time by clicking the link in the footer of our emails. We use Mailchimp as our marketing platform. By subscribing, you acknowledge that your information will be transferred to Mailchimp for processing.