* Fresh details of business links emerge over weekend
* Merkel says Wulff "doing a great job"
* Cut coalition majority makes fresh election unappealing
BERLIN, Dec 19 (Reuters) - Chancellor Angela Merkel gave her full backing to German President Christian Wulff on Monday, after fresh revelations about his links to wealthy businessmen emerged over the weekend.
Wulff acknowledged on Sunday that he had used the villas of business friends for private holidays on six occasions while he was premier of Lower Saxony, following an earlier admission he accepted a half-million euro home loan from a businessman.
The deepening scandal is giving Merkel another headache at the end of a tough year for her centre-right coalition, but on Monday she backed Wulff during a visit to Kosovo.
"I think the president is doing a great job. He has my full support," Merkel told a news conference in Pristina, her first direct backing for Wulff, who has rejected calls to resign.
Wulff had received surprisingly little public backing from ruling coalition leaders until now, a sign that many are waiting to see if more damaging revelations emerge.
Merkel and other Christian Democrats were humiliated earlier this year after rushing to defend Defence Minister Karl-Theodor zu Guttenberg over plagiarism allegations, only for him to later resign over the scandal.
"There's a lot of unease in the party about Wulff at the moment," said one senior Christian Democrat. "No one wants to come out and defend Wulff openly because everyone remembers what happened to Guttenberg. Who knows what could still come out?"
The party is already bloodied by scandals, resignations and tension over the euro zone crisis, and support for the coalition has fallen 10 points since it won power with just under half the vote in 2009.
Everhard Holtmann, a political scientist at Halle University, said Wulff's problems were now Merkel's.
"If he doesn't come up with some convincing explanations, I think it is going to be hard for him to stay in office," Holtmann said. "Merkel is staying reserved. But it could get very difficult for her if she needs to find a new president."
Wulff has only held the largely ceremonial position for 18 months since replacing Horst Koehler, the former IMF chief, who resigned after making undiplomatic comments about the usefulness of military force.
CLINGING TO JOB
Wulff, 52, denied he misled Lower Saxony's parliament last year about the origins of a 500,000-euro private loan he obtained on favourable terms from the wife of businessman Egon Gerkeens.
When first asked about it in 2010, he told parliament that he had no business ties with Gerkeens. He later repaid Gerkeens and said last week he regretted not giving the full story but has rejected calls to quit.
"No, we're not going to," he said on Sunday
Premier of Lower Saxony between 2003 and 2010, Wulff had so far been a largely uncontroversial president, and was viewed by some in the CDU as a future rival to Merkel, although he has always been careful to appear loyal.
Wulff puts Merkel and her coalition in a dilemma whether to ride out the negative headlines or risk proposing a new presidential candidate with a drastically reduced majority in the Federal Assembly which elects Germany's head of state.
Merkel's majority in the 1,244-member assembly has shrunk to just 4 compared to 22 in 2010 . Wulff only crept into the job in a third and final round of voting when he was elected last year.
"He's clinging to his job right now but no one in the government wants to see him go either," said the senior CDU official. "Everything could get very complicated if we have to go to the Federal Assembly again. Anything could happen there."
The official said Wulff had squandered a chance to defuse the scandal early last week with an apology or a clear statement when the story first broke.
"Wulff is feeling the heat from the media and in a way it's his own fault," he said. "He got everyone angry with tricky answers. And it's got worse with all these luxury holidays he went on. It's not like he didn't earn enough money to afford it himself."