Erfurt, Germany - A German state premier whose support is vital to Chancellor Angela Merkel is to remain out of action for half the year after suffering grave head injuries in a skiing accident, doctors predicted Tuesday.

Dieter Althaus, 50, was in collision with a woman skier on January 1 while both were making downhill runs in the Riesneralm resort in Austria's Styria state. The woman, Beate C, 41, was killed.

Doctors at a therapy centre said they expected Althaus to be back at his desk as premier of Thuringia, one of Germany's 16 states, "before the summer break," referring to the lull in German public life that usually takes hold about mid-July.

Althaus is scheduled to lead his party, the Christian Democratic Union (CDU), in campaigning before a state election on August 30.

The ministers who are running the state in his absence - Finance Minister Birgit Diezel and junior minister Klaus Zeh who runs Althaus's office - have studiously avoided any suggestion that he should resign.

A Thuringia election loss for Merkel's CDU would deal her a bad blow, not only suggesting that the party is vulnerable in the run-up to a federal election on September 27, but also taking the state's votes in the Bundesrat, or legislative upper house, from her grasp.

At the Schmieder therapy centre in the town of Allensbach near the Swiss border where Althaus is a live-in patient, the chief doctor, Joachim Liepert, said, "He still needs time to gain fresh strength which will be absolutely necessary to his recovery."

He suffered brain trauma in the accident. He is not expected to be well enough to be interviewed by police about the accident till next month, but doctors say he is unlikely to ever have any memory of it.

Police suspect Althhaus swerved while descending a fast slope onto a slower, intersecting slope being used by C, who was not wearing any helmet. Austrian prosecutors are considering whether to charge him with manslaughter by negligence. (dpa)