The nation's top economic regulator says China will continue to supervise speculative investment projects in key areas.

"Regulative authorities will continue to pay close attention to foreign investment in industries such as property, hotels, entertainment, cinemas and sports clubs," Yan Pengcheng, spokesman for the National Development and Reform Commission, said.

He said companies planning to invest in those industries should be cautious.

Yan said China always encourages legal overseas investment projects.

In December, regulatory bodies released a document outlining plans to tighten controls over "irrational outbound investment".

Yan's comments came after official data showed that China's non-financial outbound FDI plunged 45.8 percent year-on-year in the first half of 2017 to $48.19 billion, according to the Ministry of Commerce.