By Conor Humphries and Padraic Halpin
DUBLIN (Reuters) - Ireland's government looked set to collapse on Friday after the party propping it up submitted a motion of no confidence in the deputy prime minister in violation of a three-year support agreement.
The domestic crisis hit just weeks ahead of a European Union summit on Britain's plans to leave the EU, a large portion of which hinges on Irish issues.
Prime Minister Leo Varadkar is due to play a major role in the Dec. 14-15 summit, telling EU leaders whether Ireland believes sufficient progress has been made on the future border between Ireland and Britain's province of Northern Ireland.
The head of opposition party Fianna Fail Micheal Martin told state broadcaster RTE his party had submitted a motion of no-confidence in Deputy Prime Minister Frances Fitzgerald over her handling of a legal case involving a police whistleblower.
Martin said an election "can be avoided if the government takes action" by asking Fitzgerald to resign. The government on Friday said this would not happen, making an election all but inevitable.
Martin said Varadkar could take part in the EU summit and that parliament would be united in supporting him.
The border between Ireland and Northern Ireland is one of three issues Brussels wants broadly resolved before it decides next month on whether to move the talks onto a second phase about trade, as Britain wants.
The other issues are Britain's financial settlement on leaving the bloc and the rights of EU citizens living in Britain.
Foreign Minister Simon Coveney told parliament on Thursday the government was not yet ready to allow the talks to move on to the trade issues and needed more clarity from London.
(Reporting by Conor Humphries; Editing by Janet Lawrence)