Trump 'supports' Dakota Access pipeline

US President-elect favours controversial project which has been protested for months by tribes and green groups

US President-elect Donald Trump on Thursday said for the first time that he supports the completion of a pipeline project near a North Dakota Indian reservation, which has been the subject of months of protests by tribes and environmentalists.

A communications briefing from Trump's transition team said despite media reports that Trump owns a stake in Energy Transfer, the company building the pipeline, Trump's support of the pipeline "has nothing to do with his personal investments and everything to do with promoting policies that benefit all Americans."

"Those making such a claim are only attempting to distract from the fact that President-elect Trump has put forth serious policy proposals he plans to set in motion on Day One," said the daily briefing note sent to campaign supporters and congressional staff.

Activists have spent months protesting plans to route the $3.8 billion Dakota Access Pipeline beneath a lake near the Standing Rock Sioux reservation, saying the project poses a threat to water resources and sacred Native American sites.

On Thursday, hundreds of US military veterans started arriving at a camp to join thousands of activists braving snow and freezing temperatures to protest the pipeline.

Veterans Stand for Standing Rock will spend the day building a barracks at the Oceti Sakowin camp near Cannon Ball and coordinating with protesters who have spent months rallying against plans to route the Dakota Access Pipeline beneath a lake near the Standing Rock Sioux reservation, organisers said.

Some of the more than 2100 veterans who signed up on the group's Facebook page have arrived at the camp with hundreds more expected over the weekend.

The veterans intend to form a human wall in front of police to protect protesters.

Republican Trump has been a vocal supporter of another high-profile pipeline project, Transcanada's Keystone XL, which Democratic President Barack Obama denied a permit for last year.

Republican North Dakota Senator John Hoeven said he met with Trump's transition team to discuss the delayed pipeline.

"Today, Mr. Trump expressed his support for the Dakota Access Pipeline, which has met or exceeded all environmental standards set forth by four states and the Army Corps of Engineers," Hoeven said in a statement.

"It is important to know that the new administration will work to help us grow and diversify our energy economy and build the energy infrastructure necessary to move it from where it is produced to where it is needed," he said.