AUSTRALIAN Workers' Union secretary Paul Howes should pressure the Labor government to repeal the carbon tax, the Opposition says.
The Coalition seized on a report in The Australian newspaper which revealed the AWU wrote to its members the day after carbon pricing came into effect on July 1 saying it "didn't want the carbon tax".
AWU Victorian branch secretary Cesar Melhem signed the letter.
Opposition industry spokeswoman Sophie Mirabella accused the AWU of abandoning the country's manufacturing workers by publicly supporting carbon pricing.
"Mr Howes's belated admission that he knew the carbon tax would hurt his members is proof that he is like the senior Labor parliamentary team and is willing to say and do anything to keep Labor in power," Ms Mirabella said.
"Meanwhile, Labor remains in denial about the impact on jobs despite workers now being warned of job losses at Queensland Alumina Ltd's Gladstone refinery with the carbon tax in the mix of threats to job security.
"Mr Howes knows that the carbon tax is bad for Australian industry, it's time he stood up for his members and used his clout within the ALP to have the carbon tax repealed."
Mr Howes said last year the AWU would only support the carbon tax on the condition no jobs were lost.
He told The Australian the carbon tax was a "very hot topic" when the letter was sent.
The AWU had said all along the scheme was not something it had asked for, but was now a "reality", Mr Howes said.
Opposition climate change spokesman Greg Hunt used the letter to repeat the Coalition's promise to repeal the carbon tax if elected to government next year.