Australian Workers' Union boss Paul Howes says the Reserve Bank of Australia has signed a "death warrant" for manufacturing by putting its cash rate on hold.
But the coalition insists it is the threat of the carbon tax, which starts on July 1, that is making industry nervous.
The RBA on Tuesday kept the cash rate steady, at 4.25 per cent, contrary to most forecasts of a 25-basis-point cut.
The decision has pushed up the Australian dollar, which already is putting pressure on exporters and has led to a number of car makers and other manufacturers shedding jobs.
Mr Howes on Thursday told Melbourne radio MTR the main pressure facing the latest company to shed jobs - aluminium maker Alcoa, which operates a smelter in Geelong, Victoria - was the dollar, not the carbon price.
"This plant with a carbon price can be incredibly profitable if the dollar sits at 104, 99 (US cents, or lower)," Mr Howes said.
"But when you're sitting at 110, and when there's no signs of it coming down, when the Reserve Bank is, basically, trying to sign a death warrant on Australian manufacturing industry, yes, these jobs are under threat."
Opposition Leader Tony Abbott agrees the high dollar is an issue.
"But the thing is the carbon tax is a further structural change that will operate to the detriment of these industries," he told the same network.
Australia should have a "natural advantage" in making aluminium and steel because of its affordable energy and abundance of coal and gas.
"But because of the policies of this government, unfortunately these industries are on the way out," Mr Abbott said.
Australian Industry Group chief Heather Ridout, who joins the RBA board next week, told ABC Radio the company had confirmed the carbon tax was not a factor in the job cuts.
"I think Alcoa is saying it's not a factor. The car industry is saying it's not a factor and I think that's right," Ms Ridout said.
"I mean, you can't play politics over a lot of job losses and a lot of pain in industries.
