The Australian Manufacturing Workers Union (AMWU) says 60 jobs will be cut at a Maryborough company in southern Queensland.
AMWU spokesman Brad Hansen says CQMS Razer manufacturers mining equipment and is calling for voluntary redundancies but it is possible some will be forced.
He says 30 jobs were cut from the company in November and is concerned the work is going offshore.
"There is some downturn in the mining industry I don't believe personally that it's significant enough to cause these situations," he said.
"I think essentially these products are getting supplied from overseas."
He says seven apprentice jobs are among the cuts.
"I don't believe there is any need for CQMS to make them redundant," he said.
"Despite them going down in size, there should still be enough tradesmen to supervise and more than enough work for the apprentices to remain on site and fulfil their training contracts."
"Redundancies are difficult in any situation but when apprentices are involved it's extremely worrying."