The Forsa trade union is to hold a series of meetings over the coming days with Ryanair pilots over a pay offer from the company.
The union - formerly called Impact - is to write to the airline informing it of its plans to ballot members on the issue.
However, a union spokesperson said they see the offer as an "interim measure" pending engagement on pay following completion of a recognition agreement.
The airline has set a deadline of January 17 for its Dublin-based pilotsto to accept the offer.
Chief Commercial Officer Peter Bellew said in a memo sent to pilots yesterday: "If the Dublin pilots vote on the attached revised Dublin base agreement, with the up to 20% pay increases by the 17th January, then these increased payments will be made in the January payroll."