Sporting goods giant Nike is to review its entire Malaysian contract factory base over the next week after discovering substandard working conditions at one of its suppliers in the country.

The company said that an investigation at the Hytex Factory had found unacceptable living conditions, withholding of worker passports and garnishing of wages - all of which are "serious breaches of Nike's Code of Conduct".

Nike found that the majority of housing at Hytex was unacceptable, and said all workers would be transitioned into new Nike-inspected and approved housing within 30 days.

Following the revelations, it has also ensured all workers have immediate and total free access to their passports, and set up a 24-hour Nike hotline should they be denied access to their passports by factory management again.

The company said in a statement: "Nike takes these issues very seriously and is taking immediate action to protect the rights of workers in its Malaysian supply chain.

"We are committed to comprehensively addressing the issues identified at Hytex and to continued follow-up to help ensure changes are lasting."

Nike has also demanded that Hytex takes immediate measures including reimbursement for all current migrant workers there and provides return airfares for any worker who wishes to return home, irrespective of their contract requirements.