Fitch said today it will review Ireland's credit ratings in the light of any possible package agreed with the International Monetary Fund and the European Union.
The review will focus on the impact that possible financial aid would have on the ability of Ireland and its banks to regain access to market funding at an affordable cost, Fitch said in a statement.
The financial terms of any IMF/EU assistance and their fiscal implications would also be taken into account during the review, the agency added.
Fitch currently rates Ireland at A-plus with a negative outlook, the lowest rating assigned to the country by the three larger agencies. Moody's has Ireland at Aa2, while Standard & Poor's has it at AA-minus.
Fitch warned there is "considerable uncertainty" about possible additional losses in the country's banking system, including from residential mortgage lending.
"It's now evident that the actions taken in September have not succeeded in restoring confidence in the banking sector," it said in the statement.
Despite receiving billions of euros in public funds in September, Irish banks are still struggling to roll over existing debt in capital markets, relying instead on funding from the European Central Bank and the Irish Central Bank.
Central Bank governor Patrick Honohan said he expects Dublin to receive tens of billions of euros in loans from European partners and the IMF to provide contingency capital for its banks.