The Australian Securities and Investments Commission is investigating the Chinese firm Hanlong Mining for suspected insider trading in relation to Bannerman Resources Ltd and Sundance Resources.

ASIC obtained ex parte orders last week freezing the assets and restraining the travel of Steven Hui Xiao, managing director of Hanlong Mining, Calvin Zhu, a vice president, and Fan Zhang, an executive.

"The Supreme Court of NSW yesterday made interim orders preventing Mr Steven Hui Xiao, the managing director of Hanlong Mining, from leaving Australia until 22 September 2011, other than to visit Hong Kong between 13 and 14 September 2011 to attend to visa requirements," the ASIC said.

Freezing orders were also obtained for Xiao’s wife, Xike Hu, FanFan Chen and Wingatta Pty Ltd, an entity associated with Zhang.

Xiao consented to the freezing orders although he sought to vary the travel restraint orders permitting him to make a brief trip to Hong Kong. ASIC opposed this variation at a hearing Friday.

The Supreme Court of New South Wales modified the travel restraint order to let Xiao to visit Hong Kong and return Wednesday.

Xiao’s wife, meanwhile, was told to hand in her passport until her husband returns to Australia.

The court found that the commission had shown a solid basis for investigating whether Xiao had violated the Corporations Act's insider trading provisions.

"ASIC’s investigation is at an early stage and ASIC does not propose to comment further at this time as to the status of its investigation," it said.

In July, Hanlong Mining offered A$1.2 billion to acquire Sundance Resources, a mining firm with iron ore assets in Cameroon and the Congo. Hanlong Mining also offered A$144m for Bannerman Resources.

Hanlong Mining also has interests in seven major mining projects in mainland China.