ECB will extend asset buys beyond September 2016 if needed - Coeure

FRANKFURT (Reuters) - The European Central Bank will have to keep its expanded asset-purchase programme going beyond September next year if it does not have the desired impact by then, ECB Executive Board member Benoit Coeure said on Friday.

The ECB said on Thursday it would purchase sovereign debt from this March until the end of September 2016, launching a plan that will pump hundreds of billions in new money into a sagging euro zone economy.

"If we haven't achieve what we want to achieve, and I should say what we should achieve ... then we'll have to do it for longer," Coeure told Bloomberg TV.

"And it's not a revision of the programme, it's just that it is open-ended, it is intended to last until September 2016 and then we will reassess and we will see if this is enough or not enough," he added.

(Writing by Paul Carrel)