BERLIN, Nov. 14 (Xinhua) -- German health minister Jens Spahn, one of the three likeliest candidates to succeed Chancellor Angela Merkel as the leader of the Christian Democratic Union party (CDU), attacked his competitors Friedrich Merz and Annegret Kramp-Karrenbauer in an interview on Wednesday.

Spahn told the editorial network Germany (RND) that CDU members would not know what Merz would actually stand for and accused Merz of inconsistency. In the interview, he criticized statements made by Merz, who expressed sympathy for a European unemployment insurance system three weeks ago, but partially revoked his comments last week.

The acting health minister distanced himself from Merz whose interaction with the party would differ from his own. "I have campaigned for the party in good as well as in bad times," said Spahn. "I offer a perspective that goes beyond four years."

Merz, a former CDU parliamentarian and faction leader of Germany's conservative union (CDU/CSU), retired from politics in 2009 and has since worked at various senior management positions, most recently as active chairman of investment company BlackRock. At the end of October, Merz announced his intention to run as successor to Merkel as CDU chairman.

Kramp-Karrenbauer, current secretary general of the CDU, was also accused by Spahn who attacked her backward-looking social policy.

"I voted for the opening of marriage out of conviction," Spahn, who lives an openly gay life and is married to his partner, told the RND network.

Kramp-Karrenbauer had stated in 2015 that marriage was clearly defined as a union between man and woman.

Spahn is considered an outsider in the fight for the CDU presidency in Germany. In the latest survey of the opinion research institute Emnid conducted for the newspaper Bild am Sonntag, 9 percent said they would elect Spahn as Merkel's successor. Spahn came in third place behind Merz, who achieved 30 percent in the survey and the poll winner Kramp-Karrenbauer with 32 percent.