The organiser of an "extreme mountain race" in Germany denied manslaughter charges Monday after two participants died of cold and exhaustion running up the country's highest mountain.

"I would like to say with total conviction that I am in no way responsible for these deaths," said Peter Krinninger (54) as his trial opened in the Alpine town of Garmisch-Partenkirchen.

The two runners, aged 41 and 45, died in July 2008 not far from the finishing line at the summit of the Zugspitze, at 2962 metres.

Dressed in shorts and t-shirts, they were surprised by a sudden change in meterological conditions. Six others were hospitalised following a heavy snow storm.

Krinninger refused to pay a fine of 13 500 euros (20 000 dollars) that would have allowed him to avoid a trial.

He organised a further race in 2009 and another is planned for 2010. The best runners complete the course, just under 18 kilometres long, in around two hours.