KBC will thus withdraw from NLB and complete its strategic plan in line with an agreement with the European Commission dating from November 2009. The agreement stipulates the Belgian bank must sell its stake in Slovenia's largest bank as the shareholding does not qualify as a strategic investment.

The ministry said it was buying the stake in order to streamline the process of finding a new long-term partner for NLB.

"Since NLB is a systemic bank, the government is very much interested in having control over the process of finding a new strategic partner or investor, which is why it accepted KBC's offer," the ministry said.

The deal is expected to take place in the beginning of 2013 subject to approval from the competition watchdog.

In line with the decision, supervisors John Hollows and Riet Docx and board member Guy Snoeks filed letters of resignation effective 31 December 2012.

The development comes a day before NLB shareholders are to meet to decide on a new EUR 375m capital injection. The bank has said the proposal was of a "precautionary measure" in case of a negative turn of events "in economic and other areas".

KBC acquired a 34% share in NLB in 2002, but diverging views on the bank's long-term development among the owners became evident by 2006, when KBC reevaluated the stake into a financial investment and later decided to gradually withdraw due to its lack of influence.

In June 2012, the Belgian bank withdrew its cooperation in a capital increase aimed at improving NLB's capital adequacy, which was to increase its share from 25% to 33.9%.

The state, together with state-run funds KAD and SOD, currently holds a combined 59% stake in NLB.