DUBLIN — The Irish government announced Tuesday it won’t sell its 25 percent stake in Aer Lingus to Ryanair because a merged airline would be likely to undermine competition and jobs.

The decision by Ireland’s full Cabinet makes it harder for Dublin-based Ryanair to acquire its main Irish competitor. But in a typically defiant response, Ryanair said it still expected to take over Aer Lingus and didn’t need the government’s support.