Four Rio Tinto employees have been handed sentences of up to 14 years after being found guilty of commercial espionage and accepting bribes in China.

The sentences, handed down on Monday by a Shanghai court, are tougher than many had expected and could complicate the mining giant's and Australia's relationships with China, a key market.

Stern Hu, Rio's top iron ore salesperson in China, has been sent down for 10 years after admitting taking bribes. Hu, an Australian citizen, is reported to have received seven years for the bribery charge and five for stealing commercial secrets but the sentence was cut by two years as he admitted bribery.

His colleague, Chinese national Wang Yong, received a 14-year term which is the harshest out of all four. It is unknown why Yong has received such a stiff sentence.

Ge Minqiang was given eight years with Liu Caikui getting seven years in jail, the BBC reported.

Hu is reported to have been charged with receiving bribes of $900,000.

Rio Tinto is yet to make any written statement concerning Monday's jail terms.

The sentences represent a speedy resolution to the case as the trial only opened a week ago. On Tuesday some or all of the defendants admitted taking bribes. The bribery part of the trial was open to a select group of Chinese media as well as Australian consular officials. However, the commercial espionage part was held behind closed doors.

The four were detained in July and held for a lengthy period without charge as China looked into iron ore contracts which it said "caused serious consequences" for its industry.

They were formally arrested in mid August but China subsequently dropped the more serious charge of stealing state secrets. They were arrested, however, on suspicion of corporate espionage and bribery and the police investigation was extended by two months at the end of last year.

"A Chinese prosecutor said last month: "The accused four...exploited their positions to seek gain for others, and numerous times either sought or illegally accepted massive bribes from a number of Chinese steel firms".

The sentences come at a time when mining companies and steel mills are opening iron ore contract negotiations. Rio Tinto has recently been reported to be considering a quarterly rather than an annual pricing strategy.