The video, which has been published on the Mirror Online, was apparently smuggled out of the secretive country and depicts children as young as 5 being used for slave labour.
In the footage, the children are seen breaking up rocks and carrying large boulders as well as using tools to make repairs to the railway line.
The Daily Mirror said that the footage was smuggled out of the country by a network of informants over the year.
The images are the latest evidence of human rights violations in North Korea.
Benedict Rogers, the East Asia team leader at Christian Solidarity Worldwide told Premier News Hour that life under the dictatorship of Kin Jung-un is particularly harsh.
He said: "The regime has almost total control of every aspect of life so there is absolutely no freedom of religion, freedom of thought and on top of that there is real economic poverty as well."
Rogers added that he hoped the international community would take the footage seriously.
"If these reports are true, it adds further to the evidence that North Korea is committing crimes against humanity," he said.
"The UN carried out an inquiry two years ago now and came to that conclusion. But unfortunately, that report has sat on a shelf without any meaningful action.
"We hope the report out today will encourage the international community to take this seriously."
A 2014 United Nations report outlined human rights abuses in North Korea and found "The gravity, scale and nature of these violations reveal a State that does not have any parallel in the contemporary world."
Listen to Aaron James speak to Benedict Rogers here: