Strike action at embattled Ryanair intensified Tuesday, with German pilots the latest to plan possible walkouts over conditions, following similar moves by staff based around Europe.

Germany's powerful pilots' union said members would strike at Ryanair for better pay and conditions, although they insisted they would not disrupt flights over the Christmas holiday.

Pilots "announce a strike at Ryanair", the Cockpit union posted on Twitter.

They aim "to force the start of talks to create employment and pay conditions for Ryanair pilots in line with the market", the union said in a statement.

Ryanair had a "last chance" to avoid strikes by immediately coming to the negotiating table, union president Ilja Schulz said.