In a circular, issued on Saturday and reported on in state media, China said its goal was to strengthen supervision and ensure clean government, after several high-profile corruption cases.
Last week, more than 100 investigators arrived in the financial capital of Shanghai to probe a graft case involving government pension funds, amid suspicions that money had been siphoned off through illicit loans or investments.
In June, Liu Zhihua, a Beijing vice-mayor who oversaw Olympic construction, was sacked, accused of corruption and dissolute behaviour.
Under the terms of the circular, leading cadres are required to report to the party within a month if they or their immediate family members build, buy, rent or sell property, marry foreigners, or if they travel abroad for private reasons.
Among other rules, they must also tell their superiors if their spouses or children are under judicial investigation, if they move abroad or if they run businesses or hold high-ranking positions in joint ventures and mainland branches of overseas companies.
The circular was issued after a Politburo meeting on Tuesday presided over by Hu Jintao, the country's president.
Some analysts have said the crackdown on corruption can be part of a push by Hu, who took the helm of the party in 2002, to consolidate power by weeding out rivals, particularly in Shanghai, the power base of his predecessor, Jiang Zemin.