The Aer Lingus tie-up with the Oneworld alliance is expected to be completed within four to five weeks, the airline's board will be told today. The board will be updated on negotiations for Aer Lingus to join forces with airlines including British Airways and American Airlines.

The talks, taking place separately with the British and American airlines, are nearing completion. It is believed Aer Lingus executives will announce the frequent-flyer programme element of the deal has been agreed with American Airlines (AA).

The talks, led by Aer Lingus group's deputy chief executive Mr Larry Stanley, will entail two sets of contracts with the airlines. It will eventually lead to Aer Lingus becoming a full member of the Oneworld alliance which includes five other airlines.

It is understood that US bankers Salomon Smith Barney, which advised the Department of Public Enterprise on the merits of Aer Lingus's consultants' report recommending a strategic alliance, are keeping a watching brief on negotiations. The final deal will have to be signed off by the Minister for Public Enterprise, Ms O'Rourke, on behalf of the Government.

The deal could face delay, however, should one of the three airlines' competitors lodge complaints with regulatory authorities in the Republic, Britain or the US, or at EU level.

At present, Oneworld also includes Qantas of Australia, Canadian Airlines, Cathay Pacific of Hong Kong, Iberia of Spain and Finnair.