The Government will fight a legal challenge today, aimed at forcing the holding of a by-election, by arguing the courts can't tell the Dail what to do.
The Coalition will also commit again to holding the three by-elections early next year.
In the unlikely event of the Government losing, it would have to hold the by-elections in the next month, which would be expected to narrow its majority even further.
At the moment Taoiseach Brian Cowen has a majority in the Dail of just four votes and is dependent on independents for survival.
The High Court is to hear a case taken by Sinn Fein senator Pearse Doherty, seeking to force the Government to hold a by-election in Donegal South West.
The State will defend the action arguing the by-elections will be held next year and it is up to the Dail -- not the courts -- to decide on electoral matters.
To reassure the judge of the intention to hold the by-election, the Coalition will also reiterate its intention to hold the vote in the spring.
The case is expected to take a day and a half.
Mr Doherty is bringing the challenge to the Government's refusal to move a writ for the by-election caused by the election of Pat 'the Cope' Gallagher to the European Parliament last year.
Mr Doherty's case is built around Article 16 of the Constitution, which says members of the Dail should not represent more than 30,000 people.
Due to the delay in holding the by-elections, the two remaining TDs in Donegal South West represent more than 70,000 constituents.