A top European official says Greece and its European creditors should be able, by next week, to iron out disagreements on reforms the country must undertake to receive a new rescue loan installment.

Financial and economic affairs commissioner Pierre Moscovici said Tuesday that while significant progress has been made so far, "three or four" issues remain unresolved.

But he voiced confidence that a compromise will be found ahead of Monday's meeting of finance ministers from Greece's eurozone partners.

"We are not considering the case of failure, we are looking only for success," he said, after talks in Athens with Greek Finance Minister Euclid Tsakalotos.

Tsakalotos also said he expects talks on cutting Greece's huge debt load can start before Christmas.