Police in China have held a Singaporean banker for two weeks without allowing her access to a lawyer after her client allegedly fled the country with millions of dollars, her fiance said Monday.

Eden Wu, who has worked in Shanghai for Standard Chartered's private banking business for nine months, was detained on March 6 as she prepared to travel to Singapore for her wedding, Jason Tan told AFP.

Police are investigating one of her clients, who allegedly escaped China with his family with millions in embezzled funds, he said.

"She is being questioned every day, she can't make phone calls, and she hasn't been allowed to see her lawyer," Tan said, adding that representatives at the Singapore consulate and Wu's parents had been able to visit her on Friday.

"Her mum said she has lost a lot of weight, and that she had dark circles under her eyes," he added.

Standard Chartered confirmed Wu's detention in a statement emailed to AFP, but said the firm was unable to comment due to the police probe. "But we can confirm that Standard Chartered is not being investigated," it said.

A spokeswoman for the Communist Party committee in Wuxi city, where Wu is being held, also confirmed the detention, saying it was due to "her involvement in a bank issue."

"We cannot say more about this, as police investigations are not finished," she said. Police refused to comment.

Tan -- an American who works in the United States -- said his fiancee had been cooperating with police in their probe before her detention.

But when Wu informed them she was leaving China for her wedding, police summoned her and took her in, he said, adding authorities had not allowed him to see her because he had talked to journalists and posted information online.

"They said I could see her if I promised not to post anything on the Internet or talk to the media," he said.

"I was really shocked but I said I couldn't do that, as I feel like if this story isn't told, they will just have free rein to do whatever they want to," he said.

Wu is the latest foreigner working in China to have been detained by police in sometimes controversial circumstances.

Australian national Stern Hu -- who worked for mining giant Rio Tinto -- was detained in 2009 and eventually sentenced to 10 years in prison on bribery and trade secrets charges.

Xue Feng, a Chinese-born American geologist, was also jailed for eight years last year on state secret charges over the sale of a database on China's oil industry, despite repeated US calls to release him.