KUALA LUMPUR, Oct 21 (Reuters) - The United States has barred imports from Malaysian glove maker Supermax Corp (SUPM.KL) over alleged forced labour practices at the company, the fourth Malaysian firm to face such a ban in the past 15 months. Malaysian factories - which make everything from palm oil to medical gloves and iPhone components - have increasingly come under scrutiny over allegations of abuse of foreign workers, who form a significant part of the country"s manufacturing workforce. The U.S. Customs and Border Protection (CBP) issued a "Withhold Release Order" that prohibits imports from Supermax based on reasonable information that indicates the use of forced labour in the company"s manufacturing operations, it said in a statement on Wednesday. "With 10 of the 11 forced labour indicators identified during the course of our investigation, CBP has ample evidence to conclude that Supermax and its subsidiaries produce gloves in violation of U.S. trade law," said AnnMarie R. Highsmith, Executive Assistant Commissioner at the CBP Office of Trade. The CBP was referring to forced labour indicators identified by the International Labour Organisation that include excessive hours, debt bondage, physical and sexual violence, abusive working and living conditions. The CBP did not detail which indicators were found at Supermax and its units. Supermax did not immediately respond to a request for comment. The firm"s shares fell more than 9% in early trade on Thursday. In May, Supermax said it adhered to labour laws on the treatment of migrant workers and was committed to combating forced labour, following a media report that the CBP had opened investigations into the company. Most migrant workers in Malaysia come from Bangladesh and Nepal. Labour rights activist Andy Hall, who filed the petition to the CBP to investigate Supermax, said his interviews with the firm"s workers showed they lived and worked in "appalling conditions". He said the workers paid high recruitment fees - which resulted in debt bondage - faced unlawful wage deductions and lived in cramped conditions. Supermax did not respond to Hall"s comments. Supermax"s bigger Malaysian rival Top Glove (TPGC.KL) - the world"s largest latex glove maker - was barred by the CBP over similar allegations last July, but the ban was lifted last month after the company resolved the labour issues. read more Palm oil producers Sime Darby Plantation (SIPL.KL) and FGV Holdings (FGVH.KL) have also been banned by the CBP in the last year over forced labour allegations. Sime Darby and FGV have both appointed auditors to evaluate their practices and said they would engage with CBP to address the concerns raised.