A cabinet minister and deputy leader of Chancellor Angela Merkel's Christian Democrats (CDU) on Tuesday backed calls to demand collateral for euro zone bailouts, but her comments did not appear to be the German government's official view.

Labour Minister Ursula von der Leyen waded into the debate about Finland seeking collateral from Greece for the Finnish contribution to existing bailout payments when she told German TV that future bailouts should only be made against guarantees.

Several states are making big efforts to service their debt. This must be honored. But to keep up those efforts in the long term, collateral is needed, the minister was quoted as saying by public broadcaster ARD.

One official responded by saying her comments were not the German government's position.

So far German government officials have only made off-the-record comments about Finland's requirement for Greece to put up collateral, saying they worry this could spark copy-cat requests from other countries.

Greece agreed last week to provide AAA-rated Finland with cash collateral for the loans in a plan that did in effect spark requests for similar treatment from Austria, the Netherlands and Slovakia.

Von der Leyen has in the past been mentioned as a possible successor to Merkel, but was passed over by the chancellor in her selection of a candidate for president of Germany last year.

In her role as labor minister, von der Leyen has little direct say in euro zone policy, but the CDU is hotly debating Merkel's leadership in the euro zone debt crisis, which gets a poor review in recent opinion polls.

Analysts say any new signs of discord could fuel market fears that euro zone politicians are incapable of getting on top of the bloc's debt crisis.

(Reporting by Stephen Brown and Annika Breidthardt)