Amnesty International has released new satellite images that allegedly reveal a blurring of the boundary between a North Korean prison camp and a nearby village.

The human rights organisation says since 2006, the area surrounding the alleged prison camp Kwan-li-so in Kaechon, South Pyongan Province, has expanded.

According to Amnesty's analysis, a 20 kilometre-long perimeter has been constructed, as well as new buildings that appear to house workers, potentially designed for an expansion of mining activity.

A UN expert has also warned that North Korean authorities are essentially turning the country into "one big prison".

Amesty International's East Asia director Roseann Rife told Radio Australia's the suggest the movement of the local population is being restricted by the expansion of the prison camp.

"You see a population that had previously been outside a political prison camp for instance now surrounded by a perimeter, you have to wonder what the future holds for other such villages, inhabitants, centres of population that are adjacent to these camps.

"The fact that they've enclosed the mining activity in the valley also raises concerns about forced labour."

In 2011, Amnesty International published analysis of satellite imagery that showed the expansion of the notorious Yodok political prison camp, believed to house 50,000 men, women, and children.

According to former detainees at the political prison camp at Yodok, prisoners are forced to work in slave-like conditions and are frequently subjected to torture and other ill-treatment.

The North Korean Government denies the camp's existence.