A summit of European leaders today will focus on the refugee crisis and Britain's possible exit from the EU.
Taoiseach Enda Kenny will join the heads of the other 27 member states for the final leaders' summit of the year in Brussels.
UK Prime Minister David Cameron will tell his EU counterparts that Britain requires the ability to deny citizens from other EU countries the right to access in-work and out of work benefits for a period of 4 years and until they are eligible for a residency permit.
The highly controversial proposal is the UK's response to high levels of net migration in recent years, which the government there say is leading to a major strain on public resources.
Some EU leaders have said the UK's demands will, if passed, likely impact the very fundamental principle of freedom of movement within the EU.
Senior EU sources have said a robust debate with no taboos is expected and the meeting will go late in to the night.