* Fiscal plan due this month key for Moody's review
* Ireland borrowing costs soar on debt fears (Adds background, byline)
By Walter Brandimarte
NEW YORK, Nov 11 (Reuters) - Moody's Investors Service said on Thursday it is awaiting the release of Ireland's four-year fiscal plan later this month to decide whether to downgrade the country's credit rating.
"We intend to conclude this review in the course of December," a Moody's spokesman told Reuters.
The ratings agency put Ireland's Aa2 ratings on review for a possible downgrade on Oct. 5, citing the impact of additional bank recapitalization needs, increased uncertainty regarding the economic outlook, and elevated borrowing costs.
Ireland's borrowing costs soared to all-time highs on Thursday, further straining the debt-burdened government, as investors worried about the country's ability to service its obligations.
A possible rating downgrade could send Ireland's debt spreads even higher.
Among the big-three rating agencies, Moody's currently gives Ireland the highest credit rating, eight notches above junk status. Standard & Poor's has the country seven degrees above junk, at AA-minus, while Fitch has it one step below S&P, at A-plus.
Moody's is particularly concerned about Ireland's ability to preserve the government's financial strength in a difficult economic environment.
The four-year financial plan will be key for the government to preserve public finances and bring the deficit below 3 percent of gross domestic product by 2014, according to the agency. (Editing by Leslie Adler)