Rio Tinto's executive Stern Hu could find out on Monday if he will face a Chinese court on espionage charges, an Australian official said.

"Today is an important date because it's a deadline in terms of whether further time will be sought for investigations or in fact charges will be laid," Acting Foreign Minister Simon Crean told the Australian Broadcasting Company on Monday.

However, the federal government says there may be further delays in the case against the Australian citizen.

"There is the potential for a further extension." said Crean.

Hu, the Shanghai-based head of Rio's iron ore operations in China, was detained on July 5 along with three Chinese colleagues on suspicion of stealing state secrets.