An Apple supplier factory in China is being accused of violating labour rights and having major safety hazards following an undercover operation by China Labour Watch and Green America.

From forced overtime to exposure to toxic chemicals to a lack of safety equipment and training, the alleged worker abuses at Catcher Technology factory in China's Jiangsu Province have been laid bare in the damning report published by Green America.

Catcher, which supplies parts for Apple's iPhone 6 and formerly provided parts for the iPad, was first investigated by China Labour Watch (CLW) last year. The US watchdog catalogued the worker rights violations and in April 2013 passed its findings on to Apple.

Apple conducted a follow-up inspection and said that Catcher would carry out reforms, especially those related to occupational safety. But CLW returned to the scene in August 2014 and said that safety standards and working conditions had not improved – in fact "conditions may actually be getting worse."

"Apple and Catcher have done little to ensure that safety standards and other conditions have improved for Catchers workers," the report said.

CLW, which demands that Apple live up to its own code of conduct, found 22 labour violations at the factory, at which nearly 20,000 workers are employed.

Apple responded to the report by announcing their own investigation into the report's claims. An Apple spokesperson said in an email statement: "Apple is committed to ensuring safe and fair working conditions for everyone in our supply chain."

Apple conducted a quarterly fire inspection at Catcher last week, and addressed its concerns about the state of factory, with an Apple spokesperson admitting there are "some concrete areas for improvement."

James Wu, Catcher's CFO, said: "We are deeply concerned about the claims made by China Labour Watch, and we take the report very seriously. We are committed to following Apple's supplier code of conduct and will investigate thoroughly."