Banks managed to reduce non-performing loans to 1.9 billion euros or 4.5 percent of all loans in September from 4.6 percent a month before and 6 percent at the end of 2017.

"In spite of fast improvement of its quality, the banks' portfolio remains the worst in the companies' sector with 9.6 percent of non-performing loans," the bank said. That compares to 9.7 percent in August and 12.9 percent at the end of last year.

It also said liquidity position of the banks "remains favourable" and added that banks have sufficient capital.

Balance sheet assets fell by 0.2 percent in September compared with the previous month but increased by 3 percent year-on-year. Loans to the non-banking sector increased by 5.9 percent year-on-year.

Slovenia only narrowly avoided an international bailout for its banks in 2013. Some of the biggest banks are still fully or partly state-owned and the government controls about 30 percent of the banking sector.

The rest are mostly owned by foreign banks and investors, including US investment firm Apollo Global Management, France's bank Societe Generale, Italy's Unicredit and Intesa Sanpaolo, Russia's Sberbank and Austria's Sparkasse and Addiko Bank.