Destinations include Heathrow, Amsterdam, Budapest and Rome, airline industry sources confirmed today.

However, Heathrow slots from Shannon will be axed to make way for Belfast.

Hundreds of new jobs will be created by the decision to base three aircraft in Belfast, the first centre outside the Republic for the carrier.

The first flights will take off in October or November with Heathrow early next year.

The source said: ``The potential for growth that exists out of Belfast is one that Aer Lingus would want to pursue.

``There would be significant potential, whether its stability, whether it is business confidence.''

Aer Lingus is expected to also confirm tomorrow routes from Belfast to Barcelona; Geneva; Faro and Malaga.

BMI has enjoyed a monopoly on the Heathrow route from Belfast City Airport since British Airways pulled out in 2003.

Aer Lingus is also expected to announce plans allowing passengers to travel onwards with British Airways and Dutch carrier KLM from their London and Amsterdam hubs to destinations worldwide.

There will be three flights a day to Heathrow and two daily to Amsterdam. The others will have two to five services a week.

It could boost passenger numbers at the International Airport by 800,000 a year to over five million annually.

Belfast fought off competition from Birmingham for Aer Lingus' investment.

The company, facing price wars at its Dublin centre from Ryanair, has cut costs to reduce fares.

Several international routes from Belfast, including Rome and Geneva, will have more than one carrier.

Aer Lingus chief executive Dermot Mannion will meet staff at Shannon Airport tomorrow ahead of the Aldergrove announcement at Stormont near Belfast.

However Clare County Council chairperson Patricia McCarthy warned if the Heathrow route from Shannon is sacrificed it would be a major body blow for the west of the country.

``The Heathrow slot is a very important one,'' the independent councillor said.

``It's going to be a devastating blow, not just for Shannon but for the whole of the west of Ireland and really it's a turning of the back by Aer Lingus on Shannon.

``It's just a black bad day. They were lucrative routes and good routes and it's very hard to understand.''