BEIJING, Dec 18 (Reuters) - Corruption has been falling among Chinese Communist Party members overall, but the number of cases involving higher-ranking officials taking larger bribes has risen, a party official was quoted on Sunday as saying.

"Greed, hedonism and egoism have grown among a few officials during the development of China's socialist market economy," said He Yong, deputy secretary of the Central Commission for Discipline Inspection of the CPC (Communist Party of China).

He said an effective anti-corruption system had yet to be established, the state news agency Xinhua reported.

"At this transitional period of fundamental structural reform, loopholes exist in China's administrative mechanism," he said.

In the past two years China has prosecuted and punished nearly 50,000 party officials at various levels in the nationwide anti-corruption drive, according to the latest government figures.

But corruption remains a serious problem, He said. "The achievements of the anti-corruption campaign are still far below the requirements of the CPC Central Committee and the expectations of the common people."

On the future of anti-corruption measures, He said the CPC and government will focus on supervision and further improve the administrative mechanism.

The government has taken steps to prosecute corrupt officials accused of illegally confiscating farmers' land, embezzling public funds and delaying payment of migrant workers' wages.

State media said on Friday that the trial had begun of a local Communist Party chief for his role in one of the bloodiest in a wave of rural riots to strike the country in recent years.

In June, hired thugs killed six and injured dozens of villagers staging a sit-in on land confiscated by a state-owned power plant to protest against low compensation in Shengyou village in the northern province of Hebei.

The Shengyou sit-in was one of a series of protests in rural China, many of which have focused on land rights as rapid development encroaches on farmland. Corruption and the growing gap between rich and poor have also been flashpoints for unrest.

The government has said there were some 74,000 protests in China last year involving 100 or more people.