BERLIN (Reuters) - Further financial assistance for Greece depends on the successful completion of a review of its bailout program and the participation of the International Monetary Fund (IMF), a spokesman for the German Finance Ministry said on Tuesday.

"Further payments depend on the successful completion of the program's review and the participation of the IMF," the spokesman said.

On Monday, the head of the euro zone's bailout fund said Greece will only receive more loans from the bloc if the IMF joins its latest aid program, spelling out a condition thus far disregarded by Athens's creditors.

Greece needs a new tranche of financial aid under its 86 billion euro bailout by the third quarter of the year or it faces the risk of defaulting on its debts.

(Reporting by Tom Koerkemeier in Brussels; Writing by Joseph Nasr; Editing by Andrea Shalal)