North Korea plans to allow farmers to keep more of their produce in an attempt to boost agricultural output and supplies, help cap rising food prices and ease malnutrition.

The move to liberalise agriculture under new leader Kim Jong-un would reverse a crackdown on private production that started in 2005, and comes amid talk he is considering reforms to boost the economy.

"Peasants will have an incentive to grow more food. They can keep and sell in the market about 30%-50% of their harvest, depending on the region," a source said.

At present, most farm output is sold to the government at a state auction price that has diverged from the market rate.

The plans come as some websites run by North Korean defector groups said the price of rice more than doubled at the end of August from the start of June.