JAKARTA (Reuters) - IndustriALL Global Union, a federation of labour unions, said the Indonesian unit of copper miner Freeport McMoRan Inc and metal smelter PT Smelting had treated "fired" workers "inhumanely and with contempt", urging both to reinstate staff and contractors.
Following export restrictions related to a permit dispute, Freeport furloughed some 3,000 workers in Indonesia earlier this year, which prompted a strike and high levels of absenteeism.
Freeport later deemed that approximately 3,000 full-time and 1,000 contract employees who were absent had "voluntarily resigned."
A spokesman for Freeport Indonesia declined to make immediate comment on the allegations made by IndustriALL on Friday, referring to earlier statements by Freeport.
Arizona-based Freeport, the world's biggest publicly-traded copper miner, has repeatedly said it has acted on labour issues in accordance with Indonesian law and its labour contract, with former employees able to apply for open positions with contractor companies.
About 300 workers were dismissed from PT Smelting in January and the company said at the time that it aimed to replace them after a labour strike.
PT Smelting is jointly owned and operated by Japan's Mitsubishi Materials Corp and Freeport. A spokesperson for Mitsubishi Materials in Tokyo could not be reached for comment during a public holiday on Friday.
"Both PT Freeport (Indonesia) and PT Smelting have treated the workers they fired inhumanely and with contempt," IndustriAll Mining Sector Chairman Andrew Vickers told reporters.
IndustriALL representatives from unions in Australia, the Netherlands, South Africa and North America have been in Indonesia to push the government to "uphold fundamental labour standards" and help to get workers' jobs back.
Vickers said both Freeport and PT Smelting had acted in "clear violations" of workers' rights to organise, bargain collectively and strike.
The federation urged both companies to "immediately reinstate all the workers they have fired, then negotiate fair resolutions of the matters that provoked workers to strike in the first place," he said.
IndustriALL says it represents 50 million workers in 140 countries worldwide and has previously worked to highlight safety and pay issues in Southeast Asia's garment industry.
"In this case, resignations were an unfortunate consequence for a number of workers who had prolonged absenteeism from work despite multiple efforts and requests by the company to return to work," Freeport said on Friday ahead of the statement by IndustriALL.
Reporting by Wilda Asmarini in Jakarta; Writing by Fergus Jensen; Editing by Joseph Radford