ATHENS, Aug 11 (Reuters) - Greek Finance Minister Euclid Tsakalotos said on Tuesday minor details were left pending in talks with lenders after all-night negotiations concluded on a new bailout package to keep Greece financially afloat.

"Two or three small issues," are pending with lenders, Tsakalotos told reporters after 18 hours of talks with European institutions and the International Monetary Fund in Athens.

Greece needs up to 86 billion euros to stave off a financial meltdown and maintain its position in the euro zone. At least 3.0 billion is needed by Aug. 20 to settle a debt to the European Central Bank.

Earlier, a senior Greek finance ministry official said the two sides had agreed on a wealth fund to handle privatisations, and how to address non-performing loans in its banking sector. Both issues had been key sticking points in negotiations.

"Finally, we have white smoke," the official said.

(Reporting By Lefteris Papadimas; Writing by Michele Kambas)