Mr Hockey said the decision to disclose taxpayer information is entirely a matter for the commissioner of taxation as an independent statutory office holder.
“Confidentiality of taxpayer information has been a key feature of Australia's taxation system since the 1950s,” he said.
“The principle of confidentiality goes to the very essence of our voluntary, self-assessment taxation system. Without the continued application of confidentiality provisions, we run the risk of reducing compliance with the system."
The Treasurer used the ATO’s recent offshore income disclosure program, Project DO IT, as an example of why confidentiality is important to the integrity of the tax system.
“The benefit of this approach is evidenced in the success of the [ATO's] Project DO IT where 5,600 people came forward to self-disclose around $600 million in income and $4 billion in offshore assets,” he said.
Mr Hockey added that government is working hard to ensure multinationals pay taxes in Australia on the income they earn here, and praised the efforts of the ATO in tackling tax avoidance.
“The ATO has strong investigative powers to ensure that multinational companies operating in Australia are paying their fair share of tax,” he said.
“With additional resources, the ATO is undertaking more extensive inquiries and audits of multinational companies considered a risk to Australian tax collections.
“The ATO is embedded in the offices of dozens of multinationals operating in Australia. By 30 June 2015, the ATO will have conducted around 200 reviews of the highest risk multinationals.
“We need to promote and support this work, not put it at risk.”