By Alan Baldwin

LONDON, Jan 21 (Reuters) - Formula One's governing body has played down talk of the sport's new engine rules triggering a protest that overshadows the Australian season-opener in March.

Media reports have suggested Mercedes and Red Bull, the latter now making their own engine, may be exploiting a "grey area" in the regulations to extract more power than the Ferrari, Honda and Audi units.

Manufacturers, engine experts and the governing International Automobile Federation (FIA) are due to meet on Thursday amid increasing chatter about compression ratios and thermal expansion.

Nikolas Tombazis, the FIA's single-seater director, suggested some of the reporting was overblown and said having a level playing field, and ensuring the rules were equally well understood, was a top priority.

"Of course everyone is extremely passionate and competitive and when people are in that state of mind it does create a bit of blindness to maybe other arguments," he told Reuters at the Autosport Business Exchange conference on Wednesday.

"Some people therefore present their points of view as the only truth. Unfortunately, things are never completely simple. That's where we come in to make sure we clarify these things.

"I don't think it's as huge a topic anyway as currently is being made out in the press."

Tombazis said the meeting would discuss "some technical merits of the topic" and was not any sort of a showdown to reach a solution.

Asked if he felt the issue would be defused before Melbourne, he concurred.

"I believe we are going to be OK," he said.

"It's a top priority to make sure we don't have controversies because we want to go racing and not to be sat in courts and hearings after the first race."

Audi boss Mattia Binotto said at the team's livery launch on Tuesday that any manufacturer running an engine with a higher compression ratio would have a big advantage.

"If it's real, it is certainly a significant gap in terms of performance and lap time, and that would make a difference when we come to competition," he told reporters at the event in Berlin.

(Reporting by Alan Baldwin, Editing by Andrew Cawthorne)

((alan.baldwin@thomsonreuters.com; +442075427933;))