Germany\'s opposition Social Democrats have chosen Peer Steinbrueck, a former finance minister, to challenge Chancellor Angela Merkel in elections next year, a newspaper reported on Friday. Citing party sources, mass circulation Bild said the centre-left party had selected Steinbrueck to run against Merkel in the election that will be held in September or October next year. Bild said party head Sigmar Gabriel would propose Steinbrueck at a special meeting of the party on Monday. Steinbrueck, 65, beat off competition both from Gabriel and Frank-Walter Steinmeier, who ran unsuccessfully against Merkel in 2009. Polls show Merkel\'s conservatives hold a comfortable lead over the Social Democrats and she is expected to win a third term at the helm of Europe\'s top economy. Steinbrueck was Merkel\'s finance minister during her first term in office, from 2005 to 2009, when Germany was governed by a \"grand coalition\" of conservatives and Social Democrats.