The Tax Office is chasing BHP Billiton for more than $500 million in payments it avoided by shovelling profits overseas.

BHP has answered some of the questions it took on notice at the Senate inquiry into corporate tax avoidance.

The responses now given to the Senate Economics References Committee show that the Australian Taxation Office (ATO) is hunting a total of $522 million in unpaid tax, interest and penalties for the years 2003 to 2010.

They also revealed that BHP objects to the assessments from the ATO, which seek tax of $301 million, interest of $145 million and penalties of $76 million.

The ATO made the assessments based on the price at which BHP Billiton's Australian outlets sell their commodities to its Singapore ‘marketing’ business, BHP Billiton Marketing AG.

The Tax Office has also investigated whether the profit earned by the ‘marketing’ operation should have to “top-up tax” in Australia, in line with Controlled Foreign Company rules.

It is understood that the ATO’s audits of BHP’s activities in recent years are still underway.

BHP has negotiated a friendly tax deal with the Singapore government, which has seen it pay just $AUD154,800 in Singapore and $AUD945 million in Australia on profits of $AUD7.29 billion, which it booked in Singapore between 2006 and 2014.

One those figures, BHP’s a tax rate in Singapore is just 0.002 per cent.

The mining giant was also questioned by Greens senator Christine Milne as to how much it gave to the Minerals Council of Australia to campaign against the mining tax in 2010.

BHP said it paid the Minerals Council $4.25 million.

BHP has previously said it spent $4.2 million on its own anti-mining-tax crusade.

One of the initial suggestions to fix the massive tax-dodging of Australian companies, and international ones operating here, is to reverse the large-scale job cuts at the Tax Office enacted by the Abbott Government.