The European Commission is expected to reject Ryanair's proposed purchase of Aer Lingus.
If its €1.48 billion bid were stopped by the Commission it would be only the 20th among the over 3,000 cases considered by the European Union's executive arm since 1990.
According to a source quoted by Reuters news agency, the EC's competition department has prepared a proposed decision to present to the full Commission before a July 4 deadline.
This comes after a market test found Ryanair's latest proposed remedies for competition problems were insufficient.
Ryanair has already built up a 25% stake in Aer Lingus. Three days after Aer Lingus floated on the Irish Stock Exchange in October Ryanair bought 16% of the airline and made a €1.48 billion offer to buy the company.
A spokesman for Ryanair said the the airline has no comment this afternoon.
At the end of March the Commission sent a statement of objections about the bid to Ryanair, saying it is concerned the proposed deal would damage competition.
Subsequently, Ryanair chief executive Michael O'Leary said he would mount a court challenge if the bid were blocked.
