Michael O'Leary has told Taoiseach Brian Cowen and Transport Minister Noel Dempsey to stand up to air traffic controllers -- and allow for more strikes if necessary.
The Ryanair chief described the Government's stance as "pathetic", with thousands of passengers facing more disruption as early as tomorrow in a fresh wave of walkouts.
Mr O'Leary said we could no longer be held to "blackmail by a bunch of incredibly overpaid, underworked public/civil servants".
He added: "They are handling 25pc fewer flights, and they want a 6pc pay increase."
The trade union IMPACT said more work stoppages, like the one that turned Ireland into a no-fly zone for four hours yesterday, could last "for a longer duration".
The strike, which shut down Dublin, Cork and Shannon airports for four hours, resulting in up to 150 cancelled flights and affecting more than 20,000 passengers.
The 300 striking air traffic controllers were attacked by Ryanair's Michael O'Leary as "overpaid civil servants".
Air-traffic controllers were deciding their next step at a meeting in Roscrea, Co Tipperary, today after the Irish Aviation Authority (IAA) suspended a further two employees.
Some 12 workers had already been suspended without pay on Tuesday after refusing to operate a new software programme.
The IAA is not ruling out the possibility of more suspensions.
IMPACT assistant general secretary Michael Landers said today: "We're not going to tolerate a situation where our people are suspended but if people are not restored to the payroll then further action is inevitable."
He said both a work-to-rule and a complete work stoppage "would be under very strong consideration".
"I think if people are not restored to the payroll then further work stoppages, perhaps along the lines of yesterday or maybe for a longer duration, would be inevitable," Mr Landers said.
But the IAA said the work controllers are now refusing to do is "work they have been doing for the last two years and were doing until three weeks ago".
"Actions such as yesterday's stoppages cause distraction and uncertainty. The provision of a crucial and safety-critical service is difficult in an environment of uncertainty," it added.
Michael O'Leary meanwhile called on Transport Minister Noel Dempsey to get up off his "backside" and "tell these guys to go back to work".
Mr Dempsey had said in the Dail that the IAA was prepared to lift the suspensions.