A ballot of members of the Employee Share Ownership Trust (Esot) at Aer Lingus on Ryanair's buyout offer is due to be counted today.
About 4,600 members of the Esot - which owns 12 per cent of Aer Lingus - were entitled to vote.
Aer Lingus unions are confident that Ryanair's €2.80 a share offer for the former State-owned carrier will be firmly rejected.
Ryanair, which currently holds a 19.2 per cent stake in Aer Lingus, said yesterday it would not increase its offer for the airline.
In a letter sent yesterday to Aer Lingus shareholders, Ryanair chief executive Michael O'Leary said: "In our opinion, there is nothing in the Aer Lingus defence document or its strategy as articulated by the chief executive that justifies a price in excess of €2.80.
"Accordingly, Ryanair confirms that it will not increase its offer of €2.80 per Aer Lingus share," he added.