The selloff hit stocks of subsidiaries spanning energy, infrastructure, property and consumer businesses, led by China Resources Power Co Ltd (>> China Resources Power Holdings Co. Ltd.) which fell more than 11 percent in its worst day since July 17 last year.

"The news triggered concern over their longer term prospects especially those (firms which) rely on acquisitions to achieve growth," said Alex Wong, a director at Hong Kong-based brokerage Ample Finance Group.

"It may not be easy for them to secure new projects going forward."

China Resources Power was followed by China Resources Cement Holdings Ltd (>> China Resources Cement Holdings Limited), which dropped 5.8 percent, and China Resources Gas Group Ltd (>> China Resources Gas Group Ltd), which slid 2.8 percent.

Retail-focused China Resources Enterprise Ltd (>> China Resources Enterprise, Limited) fell as much as 6.1 percent, heading for its biggest drop since February 25, and China Resources Land Ltd (>> China Resources Land Limited) lost 3.6 percent.

The morning selloff wiped out more than $3 billion in market capitalisation, according to Reuters calculations. The benchmark Hang Seng Index <.HSI> slipped 0.3 percent.

Shares in Geely Automobile Holdings Ltd (>> Geely Automobile Holdings Ltd) - where China Resources group chairman Song Lin serves as an independent non-executive director - were also hit, falling to their lowest level in five weeks.

The Chinese car maker said in a Hong Kong stock exchange filing, however, that the investigation would not have "a material adverse impact" on its business.

Song is being investigated for "serious discipline and law violations," or suspected corruption, the official Xinhua news agency reported.

He has been removed from his post, although he has denied the allegations.

China's top anti-corruption agency, the Central Commission for Discipline Inspection, is leading the probe, which comes amid an official campaign against corruption that has already ensnared a number of executives in state-owned enterprises.

(Reporting by Donny Kwok and Lee Yimou; Additional reporting by Nishant Kumar; Editing by James Pomfret and Stephen Coates)