Ivanka Trump
Ivanka TrumpReuters

An undercover activist who was investigating a Chinese supplier for Ivanka Trump's shoe brand has been detained, according to his wife.

Reports state that the Chinese activist, Hua Haifeng, was working undercover for the United States-based China Labor Watch (CLW). The Labour Watch has claimed that the activist had witnessed examples of forced overtime labour and wage violations under the Huajian Group.

CLW also added that two more activists involved in the investigations are currently missing. The group said that the supplier also makes products for other Western brands including Karl Lagerfeld, Coach and Nine West.

The Labor Watch group has now called on US President Donald Trump to press for Hua's release, who was arrested in China.

There has been no comment from the Chinese authorities, the Trump administration or the Ivanka Trump brand yet, according to BBC reports.

Ivanka Trump
Donald Trump with daughter Ivanka TrumpReuters

CLW said that Hua was detained in the Jiangxi province on suspicion of illegally using eavesdropping equipment but allegation had "no factual basis".

The group's executive director, Li Qiang, told the BBC that the company Hua was investigating had violated workers' rights in ways that included: forced overtime, wages lower than China's legal minimum wage, managers' verbal abuse of workers, and violations of women's rights.

Li added that this was "the first time any our investigators have been detained under a criminal process" in the 17 years of investigating Chinese factories by the group.

The detained activist's wife said that she had lost contact with her husband on May 28, 2017, however the police contacted her on Tuesday to inform her that Hua had been detained by the authorities.

"I was shocked and freaked out," Deng Guimian told BBC. "I only know that my husband was investigating a factory based in Ganzhou, Jiangxi province. That factory manufactures US president's daughter's product."

"I think he was detained for that. Police told me that my husband has been detained for illegal monitoring activities," she said.

The other two activists -- Li Zhao and Su Heng -- who were investigating the firm undercover at Huajian factories in Dongguan in Guangdong province and in Ganzhou remain missing.