Ammann, already a double gold medal winner in the 2002 Winter Olympics, easily won last week's normal hill and is one of the favorites for this Saturday's large hill contest.
The FIS (International Ski Federation) has to handle this ... we have to know what is legal and what is not legal, Austrian ski jumping coach Alexander Pointner told a news conference.
Pointner later told Reuters his team had looked at the same modification in 2008 and had concluded it was too dangerous for its younger jumpers.
Pointner did not give exact details of the changes, but said the new binding allowed Ammann to increase his aerodynamic profile in the air and therefore soar further.
He has a special thing and we're just asking why he has this modification. Other nations also saw this, he said.
FIS spokesman Egon Theiner said the binding would be discussed at a scheduled meeting of ski jump team captains later on Thursday.
Austrian officials said they noticed the binding after the first day of training for the large hill on Tuesday, when Ammann jumped from a lower position than his rivals yet recorded the longest jump of the day.
Pointner stressed that he was not protesting against the normal hill result but wanted to make sure everyone competed in the same conditions.
We also tested this kind (of binding) in 2008 and for us it was clear we wouldn't use it, he told Reuters, saying the modification was designed to boost performances rather than making it safer to jump.
Our decision was that if our young jumpers compete with that kind of binding it's much more dangerous, especially on bigger hills or when it's windy, he said.
The spokesman for the Swiss jumping team could not immediately be reached for comment.