Long convoys of Chinese lorries laden with rice were seen entering North Korea after Beijing reportedly agreed to provide major food aid to Pyongyang's new regime, a South Korean activist said Tuesday.

Thousands of lorries delivered rice to the hungry North starting on January 9, said Do Hee-Yoon of the Seoul-based Citizens' Coalition for Human Rights of Abductees and North Korean Refugees.

On Monday a Japanese newspaper said Chinese leaders had agreed on the aid at a meeting on December 20, the day after North Korea announced the death of its longtime leader Kim Jong-Il.

The deliveries lasted about 10 days before the Lunar New Year holiday on January 23, Do told AFP.

As evidence, he presented pictures taken near the customs office in the northeastern town of Tumen on the Chinese side of the border on January 12.

One photo, taken from inside a taxi, showed trucks stacked with rice bags lined up on both sides of the road.

"Trucks laden with rice sacks were seen crossing the border into the North at various places including Tumen, Dandong and Jian," Do said.

"The delivery of rice aid was apparently completed within a pretty short timespan," he said, adding it was quite rare for China to provide the North with such massive food aid at one go.

On Monday China's foreign ministry urged the international community to give its impoverished neighbour more humanitarian aid.

It did not comment on a report by Japan's Tokyo Shimbun newspaper, that China had decided to donate 500,000 tonnes of food and 250,000 tonnes of crude oil.

The paper said senior Chinese officials made the decision at a meeting chaired by President Hu Jintao, in a gesture of support for the new regime headed by Kim's youngest son Jong-Un.

The North suffered famine in the mid-1990s which killed hundreds of thousands and has battled persistent food shortages ever since. UN agencies have said three million people will need food aid in 2012 and malnutrition among young children is rising despite bigger harvests.

China moved quickly to give its public backing to the young and untested Jong-Un after his father's sudden death from a heart attack.

China has long sought to bolster its neighbour with aid. It is particularly keen to avoid instability on its borders as it prepares for its own transition of power this year and its economy loses steam.

Two-way trade between North Korea and China jumped 62 percent in 2011 from the previous year, with the North doubling its exports of minerals to its major ally, South Korean figures showed Tuesday.

The Korea International Trade Association said total trade was worth $5.63 billion last year compared to $3.46 billion in 2010.

The South's government stopped its own annual major food and fertiliser shipments to the North in 2008 after ties worsened between Pyongyang and a new conservative administration in Seoul.