The government representatives, preparing next week's Eurogroup meeting of euro zone finance ministers, concluded at talks in Bratislava late on Thursday that there were three possible scenarios for what would happen with Greece at the end of June. The least likely, they think, is a successful cash-for-reform deal next week in time to meet end-June legal deadlines.

The second possibility was a further extension of the current bailout program, which expires this month at the same time as Greece must repay 1.6 billion euros ($1.80 billion) to the IMF. The third — discussed formally for the first time at such a senior level in the EU — was to accept Greece could default.

The meeting reached no decision or concrete conclusion.

Most officials argued that it was unlikely that creditors would strike a deal on reforms with Athens in time to disburse the 7.2 billion euros that remain available to Greece under a rescue program extended in February for four months.

"It would require progress in a matter of days that has not been possible in weeks. The reaction of the ECB, the IMF and several member states was extremely skeptical," one official familiar with the discussions said on Friday.

The Greek representative at the meeting said Athens would do everything to reach a deal in time, other officials said. That would in effect mean an agreement in time to be endorsed by the Eurogroup when it meets in Luxembourg late on June 18.

Officials said, however, that even then, disbursement of loans to Athens by June 30 would be very difficult because of the time needed to finish all the legal procedures necessary.

Therefore, their second scenario was that the current bailout would be extended to keep the 7.2 billion euros, and 10.9 billion euros set aside for Greek bank recapitalization, available for Athens once a reform deal is reached later.

The money will otherwise disappear and a new bailout agreement would be needed to secure further financing.

Various extension deadlines were discussed, varying from a few weeks to the end of the year or even to the end of March 2016, to align the euro zone's program with the end of the IMF bailout package for Greece.

Such an extension would entail imposing further conditions on Greece and could involve the disbursement of funds in tranches as those conditions were met.

Representatives of some euro zone countries, however, believe that governments should prepare for a third scenario — that of a Greek default.

"For the first time there was a discussion of a 'Plan B' for Greece," a second official said. Two other officials confirmed that such a debate took place.

So far euro zone officials have refrained from discussing such a possibility, even in closed-door meetings such as the one on Thursday, even though some governments, including Germany, have been preparing for it on their own.

The discussion was very theoretical because the scenario of a euro zone country defaulting within the currency union would be without precedent. The meeting came to no conclusion on it.

But officials said such a scenario would almost certainly involve Greece imposing capital controls to prevent an outflow of euros from the country and could also entail the issuance of IOUs by Athens as an alternative means of payment.