Greece would need an additional 13-15 billion euros to finance a two-year extension to meet its budget targets but is confident of bridging that gap without burdening European taxpayers, Finance Minister Yannis Stournaras told Reuters on Tuesday.

He also confirmed that the country's fiscal gap to hit its 2013 and 2014 targets remained at 13.5 billion euros. Athens has been discussing fiscal measures worth that amount with its European Union and International Monetary Fund lenders.

"We estimate the funding gap that would be created if we get the two-year extension at 13-15 billion euros," Stournaras said.

Greek officials have previously said such a gap could be covered through the issuance of short-term debt or by seeking lower interest rates or a rollover of debt held by the ECB.

(Reporting by Lefteris Papadimas)