Macarthur Coal Ltd announced Tuesday that it is "not inclined" to accept the reduced bid of Peabody Energy Corp.

"We are not inclined to take a discount in price based on a tax that may never be introduced, " said Macarthur chairman Keith De Lacy.

De Lacy stressed that the proposed 40% super profits tax on mining resources has created uncertainty in the market.

Earlier this week, Peabody lowered its previous $16 a share bid to $15, valuing Macarthur Coal at $3.8 billion. Macarthur Coal had advised its shareholders not to do anything yet and to wait until the fate of the proposed tax scheme has been decided.

"It's very difficult. We think the resources super tax is turning into such a fiasco that it will never be delivered," said De Lacy. "So we don't want to be recommending to shareholders to sell their company on the basis the tax will be delivered."

De Lacy said that Peabody's lowered bid reflects a new attitude to resource investment in Australia following the announcement of the Rudd government to super tax non-renewable energy sources to 40 per cent.

The planned super profits tax has garnered opposition from mining industry executives and stakeholders. Global mining firms Xstrata PLC and BHP Billiton warned that the tax proposal will impact their future investments in the country. Xstrata PLC suspended its copper exploration in Australia, and BHP Billiton warned that decisions on key expansion projects would be difficult until the final status of the proposed tax scheme is known.