The appointment of Irishman David O'Sullivan as EU ambassador to the United States will be announced early next week, the Irish Times understands.

David O'Sullivan, a senior official with the European Union, will be named by EU high representative for foreign affairs Catherine Ashton as the new EU ambassador to Washington as early as Tuesday.

Mr O’Sullivan will take up the four- year position in September, leaving his current position as chief operating officer of the EU’s foreign affairs wing, the European External Action Service (EEAS).

The appointment of an Irish candidate to the position will be seen as a coup for Ireland, less than five years after former Taoiseach John Bruton completed his term as the EU's ambassador to Washington.

A graduate of Trinity College Dublin, Mr O'Sullivan began his career in the European Union in 1979, moving swiftly up the ranks to become secretary general of the European Commission under Romano Prodi. In late 2005 he stepped down as the EU's highest-ranking civil servant and was replaced by Irish woman Catherine Day, taking up a position as director general of the European Commission's trade division.

Following the establishment of the European External Action Service, under the Lisbon Treaty, Mr O’Sullivan became its chief operating officer, playing a key behind-the-scenes role in EU foreign policy negotiations.

Mr O’Sullivan’s experience in EU foreign affairs and trade will be perceived as key attributes as he takes up his role. Ongoing negotiations between the EU and the US on a trade agreement are likely to dominate transatlantic relations in the coming years, while the crisis in Ukraine has pushed the question of EU-US co-operation, and particularly the role of NATO, into the spotlight.

Mr O’Sullivan replaces the former Portuguese EU official, Joao Vale de Almeida, as ambassador.