An Australian man working on the Chinese mainland has become the first defendant to be found guilty by a Shanghai court of smuggling precious metals, after he attempted to leave the municipality with 2,900 grams of undeclared gold.

Chen Ying-cheng, who was born in Taiwan in 1979, was given a suspended sentence of two years and six months on Tuesday by Shanghai No 1 Intermediate People's Court, which also ordered Chen to pay a 100,000-yuan ($16,500) fine and for the gold to be confiscated.

Chen, who co-manages a commercial management company, Yujing Wenhua, in Changshu city, Jiangsu province, was booked to fly with Air China from Shanghai Pudong International Airport to Taiwan on July 27, but was found by customs to be carrying 47 gold bars of various sizes in his carry-on laptop bag, undeclared.

"I didn't make a declaration about the gold because my grandmother was critically ill in Taiwan and I was in a hurry," said Chen, who moved to Australia with his family during his junior high years.

The gold products were gifts from relatives and friends for his engagement in 2012, he said. "I intended to go back to Australia for the wedding and to settle down after visiting my grandmother in Taiwan. So I carried them with me."

The prosecutors said the request to declare gold and other precious metals is explicit on the Customs Declaration Form in both Chinese and English.

But the defendant said he was not clear about the laws in China so did not make a declaration.

"I was clear that stealing and robbing are against the law, but the gold wasn't gained by stealing or robbing. I wasn't aware my behavior was smuggling," Chen said.

The court said punishment for a defendant cannot be exempted if he or she is ignorant of local laws, but Chen was sentenced with a reprieve because the prosecutors did not question the source of the gold bars after investigations and Chen did not hide the gold bars intentionally.

In his final statement, Chen expressed his regret.

"I came to the Chinese mainland to make a contribution. I wouldn't have acted this way if I knew it was illegal," he said.