* China foreign minister has tight schedule -spokeswoman
* W. Australia premier urges dealing Rio case quickly
* Chinese firms welcome to invest in West Australia (Recasts, changes dateline)
By Ben Blanchard
PHUKET, Thailand, July 21 (Reuters) - China's foreign minister has no plans to meet his Australian counterpart on the sidelines of a meeting in Thailand, a Chinese spokeswoman said, dashing Canberra's hopes for high-level talks on detained Rio Tinto employees.
Earlier on Tuesday, Australian Foreign Minister Stephen Smith said he hoped to raise the detentions of the four Rio staffers in China with Yang Jiechi at a regional security meeting in the Thai resort of Phuket this week. "At the moment there are no arrangements for this," Chinese Foreign Ministry spokeswoman Jiang Yu told reporters when asked if a meeting would take place. "I've not heard that there are any arrangements for this as minister Yang's schedule is very tight. He already has many bilateral meetings arranged."
Yang declined to comment upon his arrival in Phuket.
Chinese authorities this month detained the four employees, including Rio's top iron ore salesman in China, Australian Stern Hu, alleging they were involved in stealing state secrets.
Australian officials have been frustrated by the lack of any further details from China about the charges. A meeting between Smith and Yang would be the highest-level meeting yet on a case that has strained Australia-China ties.
"If my Chinese counterpart is there, I hope to have the opportunity to speak to him about Stern Hu," Smith earlier told Australian state radio.
China is Australia's biggest trade partner, with trade worth $53 billion last year. Iron ore exports injected $14 billion of that, led by Rio Tinto and BHP Billiton Ltd.
Rio has defended its employees, saying claims they bribed Chinese steel mills were unfounded.
CHINA URGED TO HANDLE CASE QUICKLY
Keeping up the pressure on Beijing, Western Australia's premier said he had urged the Chinese government to handle the detentions quickly to prevent hurting long-term ties.
Colin Barnett raised the case at the end of a business-focused meeting with the mayor of Shanghai.
"I sincerely made the point that we respect China's legal system ... however I did say that I had concern for Mr. Hu and his family and also that we hope the case could proceed as quick as possible," Barnett told reporters.
Last week China's Foreign Ministry told Australia to stop "whipping up" the case.
"I think Australians have made too much of this. Of course, it's their citizen but China also has to act according to its laws, and can't issue a laundry list of charges while the investigation is underway," said Shen Shishun, director of the Centre for South Pacific Studies at the China Institute of International Studies in Beijing.
Barnett told reporters later that Chinese investments were welcome in Australia and very welcome in the state of Western Australia, noting Chinese firms could take a small stake in major projects and a larger stake in small projects.
In June, a $19.5 billion plan for Chinese state-owned aluminium firm Chinalco to substantially increase its stake in Rio collapsed when Rio joined forces with BHP Billiton's iron ore operations.
Barnett said he was concerned the case had the potential to cause a rift in the bilateral relationship if it dragged on.
Shanghai mayor Han Zheng, also a member of the Communist Party of China's Central Committee, pledged to "pass the message to relevant authorities", Barnett added.
The Australian government and Rio have said the detentions will not affect trade, while an influential opposition lawmaker has warned the detentions could result in tighter laws covering investment in Australian resource firms by entities controlled by foreign governments, including state-owned Chinese firms.
(Additional reporting by the Shanghai newsroom and Rob Taylor in Canberra, Writing by Dean Yates, Editing by Jeremy Laurence)