SYDNEY - Australian voters are growing increasingly hostile to the government's plan to tax carbon emissions, with almost two-thirds opposed to the scheme, according a new opinion poll.

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The poll of 1,400 people, carried out at the end of last week and published in Fairfax newspapers on Monday, found that 59 percent of respondents opposed the plan, up three percentage points from the last survey in March.

Emissions-intensive exporters such as steel companies BlueScope and OneSteel and the coal industry have raised concerns that a carbon tax would hurt their international competitiveness and cost thousands of jobs.

Trade unions, traditional supporters of the ruling Labor party, have also voiced growing concerns at the tax, which would start in July 2012, ahead of an emissions trading scheme three to five years later.