Riders will now be disqualified at elite-level equestrian events if they have shaved or trimmed sensory whiskers on their horse's muzzle.

The Fédération Equestre Internationale (FEI) policy will impact events worldwide that are regulated by the international body, including the Olympics this month.

In the past, the practice has been common — particularly is showing disciplines, such as dressage — to make a horse appear more polished.

But veterinarian and animal welfare expert Professor Paul McGreevy said the discussion about banning the practice had been going on for more than 20 years.

He said the whiskers — also known as vibrissae — are a key aid to horses "detecting the world around them".

"Because the horse has a long nose and the placement of its eyes, it needs some sort of sensory system that tells it where it is in space as it approaches the ground or goes past a vertical upright.

"And that keeps the horse safe from injury."

More levels likely to be included in ban

The policy is likely to be adopted by Australia's peak equestrian body, Equestrian Australia (EA), later this year, according to EA's Christine Armishaw.

"EA definitely agrees that it's a safety and welfare issue, so we are in discussions at the moment," Ms Armishaw said.

Professor McGreevy and Ms Armishaw agreed the practice was only common within some disciplines.

"I would argue that the majority of people involved with horses don't trim their whiskers already, but then there's some who religiously do," Ms Armishaw said.

Professor McGreevy labelled the practice a "disservice" to apply human values to animals.

"[A horse] wants to feel safe, and whiskers help them," he said.Ms Armishaw said the new rule would see competitors "still on a level playing field".

"So it's really actually a non-issue as far as impacting their sport goes," she said.

Will this rule ever become law?

University of New South Wales public policy senior lecturer Siobhan O'Sullivan said often industry bodies would lead animal welfare changes ahead of government policy.

"One of the ways they can achieve their objective is to actually get the ball rolling outside the context of law-making, because governments, unfortunately … are followers," Dr O'Sullivan said.

"It strikes me as the kind of reform that could be very effective.