A video has emerged of protesters at the Standing Rock reservation in North Dakota erupting in cheers as a herd of wild bison suddenly appear at the site.

Native Americans and supporters have been protesting the construction of the Dakota Access Pipeline, which would travel underneath the Missouri River, a primary water source for the Standing Rock Sioux tribe.

The tribe says the pipeline would not only threaten their regional water supply, but also traverse sacred sites.

The video uploaded by Vimeo user videobuzz begins with a conversation between an unknown protester and interviewer, before the buffalo are noticed and the demonstrators begin cheering.

"Look at all those Buffalo! Look at all those buffalo there!" the protestor yells. "These are sacred animals, they are very powerful."

The buffalo, or American bison, is considered a sacred animal and religious symbol among Native American tribes.

Protests at Standing Rock reservation have escalated this year, with law enforcement officials arresting 141 people on Friday, using pepper spray and armoured vehicles to clear hundreds of activists.

Actress Shailene Woodley was arrested in early October at a demonstration against the pipeline.

The NZ$5.5 billion pipeline, to be built by Texas-based company Energy Transfer Partners, is designed to transport up to 570,000 barrels of crude oil from North Dakota to Illinois daily.

Newshub.