A leading business group believes the Federal Government should scrap its controversial mining tax rather than try to fix it.

The Australian Chamber of Commerce and Industry, which has always opposed the minerals resource rent tax, says it is an inefficient tax that is not raising any money.

Nor was it doing the things the government claimed it would do, such as funding a company tax cut, it said.

The MRRT in its first six months of operation has raised just $126 million against a full-year forecast of $2 billion.

"We think (the MRRT) should be abolished, there's no point trying to adjust it," ACCI chief economist Greg Evans told reporters in Canberra.