Mr Laird and other protesters have spent over a month marching from Sydney to Australia's rooftop to protest against the laws protecting feral horses in the national park.

Scientists found feral horses, and other feral animals, were damaging Kosciuszko's riverbanks, spreading weeds, destroying habitats for native wildlife and polluting waterways and bogs.

One of the few who walked the full distance, Mr Laird said it was challenging, exciting and hard work.

"It was pretty emotional," Mr Laird said

"You're part of something which hopefully will be seen as a major protest against the growing encroachment into our national parks of people who really don't have the interests of the national parks at heart."

The protesters reached the top of Mount Kosciuszko on Saturday with Mr Laird leaving Sydney on November 3.

The walk covered a distance of about 560 kilometres, which saw about 500 people walk sections with five people trekking the entire distance.

Mr Laird, with the group Save Kosci, said hard-hoofed animals like feral horses - brumbies- or pigs and deer were causing damage to an environment that had never evolved to handle them.

"It's a place of tranquillity, it's a place where you can relax and get away from the pressures of the world," Mr Laird said.

"This is part of the real Australia."

In July, the NSW government passed laws which prevented the culling of brumbies and issued protections for the.

The last survey of brumbies in the park estimated a population of about 6,000 ranging from the Victorian border to the ACT.

A vegetarian himself, Mr Laird said he loved animals but feral animals did not belong in national parks which would take decades to recover from the damage.

The horses are mainly eating native moss, which retains water and helps filter the rivers and bogs in the Australian alps, and also damage the river banks with their hooves, polluting the water.

The damage also destroys habitats for native animals like the broad-toothed mouse or endangered Corroboree Frog.

Another protester, Esther Gallant, said some of them had encountered some abuse from drivers, including people who swerved their cars towards protesters.

"But a lot of people gave them them the thumbs up and waved at them and tooted," Mr Gallant said.

Mr Gallant said after working on the protest against the new laws since July it was a high to join other walkers for the last leg on Saturday to the top of Mount Kosciuszko.

Flying a short distance from the protest site, HeliSurveys chief helicopter pilot Colin de Pagter looked down at the alpine region.

"Special country isn't it," Mr de Pagter said.

Closer to the Victorian border, Mr de Pagter looked at the damage a local feral horse population had done.

"An independent scientific reference group looked at the horses issue in the national park,"

"They agreed that they should remove the horses at that stage from a number of 6000 to 600."

Mr de Pagter said he didn't understand why he needed to convince the NSW government to remove the brumby population when qualified scientists had proven the effect they were having on the park's environment.