According to the prime minister, the EU fiscal pact will be among the toughest nuts at the two-day summit which has begun today.

The pact is by far the most important step towards stabilising the euro zone and will require strong participation from the member countries, Janša stressed, adding that Europe will not be able to rely on ad hoc measures in the future.

"The fact is that the eurozone crisis is stabilised, at least for the time being, both by the fiscal pact and the action of the European Central Bank, but of course this does not paint an identical picture for all member states," Janša said.

Several countries will need to take tough measures, and Slovenia is among them. "But this work will be easier if there is less of instability in out neighbourhood," the prime minister said.

Monday will see talks between leaders of parliamentary parties continue. Janša hopes that there would be willingness for the quick amending of the Constitution to include the so-called golden fiscal rule, which is the basis of the fiscal pact.

The pact, agreed at the end January, is expected to be signed on Friday. It will enter into force when at least 12 members of the eurozone ratify it in national parliaments.

"It is in our common interest...for this to happen as soon as possible, this year at latest," Janša said.