The Irish Aviation Authority has said that the ash cloud from Iceland's Grimsvotn volcano will have no impact on Irish airspace for the next 48 hours.

Irish flights will be able to operate between now and Friday afternoon, it added.

The IAA said it sees no change in the situation and expects normal operations to continue.

The ash cloud is expected to dissipate overnight, air traffic agency Eurocontrol has said.

‘Tomorrow, we do not expect any significant impact on European airspace,’ Eurocontrol said.

About 450 flights were affected in Germany mainly at Berlin, Bremen and Hamburg airports, the agency said.

It is business as usual at Dublin airport, according to the Dublin Airport Authority, with just one flight cancelled today - a Ryanair flight to Germany.

Earlier, Met Éireann said there is a chance that volcanic ash could enter Irish airspace tomorrow.

Meteorologist Jean Byrne says any particles will clear on Friday, but UK airspace could be at risk.

However, the long-term forecast for the UK and Ireland looks positive with little possibility of ash in airspace after the weekend.

The news comes as the eruption at the Grimsvotn volcano dies down and is no longer spewing out ash.

'There are indications that it's ceasing really,' said Hrafn Gudmundsson, a meteorologist at the Icelandic met office.

He told Reuters that mainly steam was coming from the crater, with no ash plume detected since 0300 GMT.

'I am cautiously optimistic the main ash-producing phase of this eruption has now ceased,' Dr David Rothery of Britain's Open University Volcano Dynamics Group said.

After the eruption, the most powerful by Grimsvotn since 1873 and stronger than Eyjafjallajokull that caused air traffic chaos last year, a massive plume of ash spread across northern Europe.

Flights in Scotland and northern England were cancelled yesterday. Today, three German airports - Bremen, Hamburg and Berlin - closed but have since reopened.

Dutch airline KLM resumed flights to affected destinations after a brief break.

European air traffic agency Eurocontrol said 500 flights had been affected yesterday and 450 flights were cancelled today over Germany.

Eurocontrol said the ash could would drift to Poland, but a Polish air traffic control official said no traffic limitations were due.

Meanwhile British Transport Secretary Philip Hammond has described as 'irresponsible' remarks by Ryanair's Chief Executive Michael O'Leary following the carrier's decision to send a test plane up into Scottish airspace to test ash levels.

Mr O'Leary said the plane had not encountered any ash and that the UK’s Civil Aviation Authority should allow flights in Scotland.

But Mr Hammond said that the Ryanair test flight had not passed through any high-density ash areas.