STOCKS

* Govt says China to say Friday if trail will be opened

* Trade Min says Beijing should stay out of ore negotiations (Adds details, background)

CANBERRA, March 19 (Reuters) - The trial of four Rio Tinto (RIO.AX) staff charged with commercial spying will not affect Australia's resource trade with China or sensitive iron ore price negotiations, Trade Minister Simon Crean said on Friday.

"If there were links, you would have expected the trade had fallen, yet last year China became our largest trading partner. The two matters are separate," Crean told Australian radio.

"We've never sought to make any link and neither have the Chinese in their discussions with us."

China arrested four Rio staff members, including Australian citizen Stern Hu, last July and will start their trial in Shanghai on March 22 on charges of bribery and stealing business secrets. 

Australia expects to hear on Friday whether China would reverse an earlier decision and allow full access to all parts of the trial for foreign diplomats, Australia's Foreign Minister Stephen Smith said earlier.

"I'll then make a judgement about what further representations if any are appropriate," Smith said.

China's foreign ministry has warned Australia against "politicising" the trial over the court's decision to hear bribery charges in open court, but close the trial to deal with charges of infringement of commercial secrets.

China is Australia's biggest trade partner, with trade worth $53 billion last year. Australia shipped $15 billion in iron ore to China in 2008, or 41 percent of Chinese iron ore imports.

But the Rio case has placed a cloud over contentious iron ore price negotiations underway between Chinese steelmills and the world's three largest iron ore miners: Brazil's Vale (VALE5.SA), Rio and fellow Australian miner BHP Billiton (BHP.AX) (BLT.L).

Rio's China team managed details of term contracts for iron ore, a necessary raw material for China's vast steel industry, as well as tracking market information.

Crean said Beijing could keep the trial completely separate from the delicate iron ore talks, despite pressure from Chinese steelmakers for Beijing to become involved in the negotiations.

"We've told them that we're not going to deal government to government. We recognised China as a market economy status. We keep telling them they've got to act like one," he said.

"It's market forces that determine the price and I must say that there hasn't been a representation made to us by government recently."