The trial involving four Rio Tinto employees in China ended without a verdict on Tuesday.

In the three-day case against the Shanghai-based executives, including Australian national Stern Hu, those accused pleaded guilty to charges of bribery and theft of commercial secrets.

They did not, however, agree with amounts alleged by the government.

It is expected to be days before a verdict is met and before the Rio staff find out if they will be sentenced to the minimum five years for bribery.

Australian diplomats and other foreign observers were barred from observing parts of the trial dealing with the commercial espionage, according to the BBC.

The trial, which opened on Monday, has increased concerns among the foreign business community in China.

Anglo-Australian miner Rio Tinto is one of the most profitable foreign companies operating in China, earning $10.69bn revenue last year.

The men in question were arrested in China last July as annual iron ore price negotiations were being carried out.