"While we view this as a positive development, progress in other key areas such as the banking sector and structural reforms remain prone to setbacks," Fitch wrote in its report, pointing to referendum threats.

Should reform process continue to face blockades, this could build pressure on Slovenia's rating, the agency said.

Fitch goes on, saying that the bond issue, which attracted bids worth more than four times its final size, reduced the "likelihood of a request for financial assistance from the EU", but the risk, which was at the heart of the agency's downgrade of Slovenia's rating to A-, has not disappeared yet, which is why the outlook remains negative.

Analysts at the agency moreover assessed that "the potential burden of bank recapitalisation could reach 10% of GDP", which would likely have to be shouldered by the state, while the government believes that recapitalisation costs after the transferral of bad claims to a bad bank, should not exceed one billion euros.

Fitch also said that the strong demand for Slovenian US$-denominated bonds likely reflected the "improved investor sentiment towards eurozone sovereign debt", spurred by ECB's decision to buy the bonds of troubled countries that meet the regulator's criteria.

The collected EUR 1.7bn should suffice for covering all remaining budget needs for 2012 as well as more than a half of financing needs in 2013, according to the firm.

"While its refinancing needs for 2013 and 2014 are moderate at a forecast 4-5% of GDP in each year, Slovenia will need to demonstrate that it can borrow in the bond market on reasonable terms on a regular basis to fund the public borrowing requirement and bank recapitalisation," Fitch noted.