According to undercover reporters from Asia Press, one man dug up his grandchild's corpse and ate it. Another boiled his own child for food, the report said.
People in the farming provinces of North and South Hwanghae are battling starvation after a drought. Shortages were compounded by party officials who reportedly confiscated food.
North Korea was hit by a famine in the 1990s -- known as the Arduous March -- which killed between 240,000 and 3.5 million people.
"In my village in May, a man who killed his own two children and tried to eat them was executed by a firing squad," the daily quoted an informant as saying.
The informant said the man killed his eldest daughter while his wife was away on business and then killed his son because he had witnessed the murder.
When his wife returned, the man told her they had meat. But she became suspicious and contacted officials.
Jiro Ishimaru from Asia Press which compiled a 12-page report, said: "Particularly shocking were the numerous testimonies that hit us about cannibalism."
Undercover reporters said food was confiscated from the two provinces and given to the residents of the country's capital Pyongyang.
In a village in Chongdan county, a man "who went mad with hunger boiled his own child, ate his flesh and was arrested", said an official of the ruling Korean Worker's party.
UN officials visited the area during a state-sponsored trip but local reporters said it was unlikely they were shown the famine-hit areas.
This is not the first time that cannibalism has been reported in the country.
In May 2012, South Korea's state-run Korean Institute for National Unification said one man was executed after eating part of a colleague and then trying to sell the remains as mutton.
In 2011, one man killed and ate a girl, while another man was executed after murdering 11 people and selling the bodies as pork.