CANBERRA, Oct. 10 (Xinhua) -- One in six of Australia's black coal mines could shut down with the loss of more than 21,000 mining-related jobs under the carbon tax, a report showed on Monday.

A report, released by ACIL Tasman economic consulting firm, showed 12 of the 30 underground mines in New South Wales and six of the 42 open-cut mines in Queensland are at risk of closing prematurely under the planned carbon tax. It also estimates that 27 percent of jobs in the sector are under threat.

According to Australian Coal Association's Chairman John Pegler, this is not the right time to introduce a tax, because international competition for investment in new coal mining projects is intense.

"This report sounds the final warning to the federal parliament of the consequences of the carbon tax," he said in a statement on Monday.

"Any increase in the cost base of projects in Australia will very quickly render them uncompetitive and drive this investment offshore to our competitor countries."

The data comes two days before parliament's lower house is expected to approve the government's carbon pricing package.

The 24 U.S. dollars a tonne of carbon tax is expected to start from July 1, 2012. The tax is set to increase 2.5 percent each year for three years, and will switch to Emissions Trading Scheme in 2015.