Caterpillar Inc, Komatsu Ltd and Volvo AB - leading providers of machinery to Myanmar's jade mines - have done little to address warnings about rampant abuses in the multibillion-dollar industry they supply, a Swedish charity says.
Stockholm-based Swedwatch, which focuses on business activities in developing countries, said the three firms still dominate the machinery market in Hpakant, a mining township in the restive Kachin state that supplies 90 per cent of the world's jade.
Myanmar's poorly regulated jade mines help finance a long-running conflict between the army and armed ethnic groups, and the report said the industry contributed to land degradation, water pollution and landslides that kill hundreds of people each year.
"The global mining machinery companies' seemingly blatant lack of safeguards in response to this context is a matter of serious urgency," Swedwatch said in a report on Wednesday.
It said US machine maker Caterpillar and Japan's Komatsu "still have not attempted to identify the negative human rights impacts related to their products in Myanmar".
Volvo did engage human rights consultants to conduct due diligence following an initial report by the charity in 2018. The Swedish company said the probe had absolved it of any responsibility.
"As a machinery provider, we do not believe we are responsible for human rights violations ... where our products are not directly responsible for the harm caused," spokeswoman Anna Abenius told the Thomson Reuters Foundation.
"This was confirmed in our work with the human rights expert organisation."
A Caterpillar spokeswoman declined to comment on the situation in Myanmar and referred to a statement on the company's website about its commitment to international standards on human rights.
Komatsu did not respond to requests for comment.
When asked about the charity's warnings two years ago, Komatsu said it would not sell to companies found responsible for "adverse human rights impacts," and that it had not received such reports from Myanmar.
Myanmar's jade production was worth some $US31 billion in 2014, according to human rights charity Global Witness.
Myanmar's military - known as the Tatmadaw and widely accused of human rights abuses in Kachin state and elsewhere - dominates the industry, the United Nations said following a series of fact-finding missions last year.
It said the Tatmadaw's involvement in jade and ruby mining "benefited from and directly contributed to international human rights violations in conflict-affected areas in Kachin state", warning of the ethical implications of doing business there.