Local authorities, especially in rural areas, often have close ties with triads and sometimes resort to the mafia-style use of intimidation and force during the acquisition of land and relocation of peasants for development projects.

The magazine said more than 4,000 organised-crime cases had been reported in the first nine months of the year. They involved more than 15,000 people, including 47 public officials.

Heilongjiang province was a case in point, with more than 1,400 organised gangs having been smashed between 2000 and the first half of this year, it said.

'They used illegal means to prosper and gain social clout, which in turn helped them accumulate more wealth,' the magazine said. 'It's becoming a vicious circle and is seriously destabilising economic order.'

Lian Baoshan , a triad boss in Harbin , Heilongjiang's capital, used force to beat off rival bidders in seizing housing development projects in the city, it said. Ironically, he began building his triad in the early 1990s, when China started setting up special agencies to prevent and control organised crime. His personal wealth had swollen to more than 10 million yuan since 1993, Outlook said.

His gang's sway became so strong that it infiltrated the city's economic and legal sectors. Police ran up against 'great difficulties' during investigations because 'his friends were all over the courts and police stations', it said.

The central government has recently intensified its propaganda campaign to build 'social harmony', which means maintaining social order by pacifying the disgruntled poor who were left out of the country's economic boom.

Xinhua reported yesterday that the government was considering introducing an inheritance tax as soon as possible to help narrow the gap between rich and poor.

Increasing income disparity, corruption and pollution are among the factors giving rise to social strife - a key concern of the Communist Party given its preoccupation with stability.