New laws to put strain on ATO

"Next year, part of our work is implementing these major legislative proposals, so we're going to be squeezed in terms of our capabilities across the board," Mr D'Ascenzo said.

Both the carbon price and the resources rent tax go into operation on July 1 next year, while the Gillard government's Stronger Super reforms are set for July 1, 2013.

Mr D'Ascenzo said setting up databases required under the Stronger Super reforms was "a really challenging piece of work for us".

He said the policy required the Tax Office to "insource" backroom work done by funds and set up a website where workers can view their superannuation positions. When complete, the system will also validate the details of accounts and help workers consolidate multiple accounts.

"That's a big risky project for me next year," Mr D'Ascenzo said.

He said the project would encourage businesses to do more online, reducing compliance costs and making them more efficient.

The Tax Office's initial role in administering the carbon price would be limited to fuel tax credits, Mr D'Ascenzo said. "We may well be right in there when you have a permit trading scheme, but at this stage that's not in place for another few years."

However, the new mining tax, which will be imposed on iron ore and coal producers with annual profits higher than $75 million, will be administered by the Tax Office.

"We've got a big responsibility in relation to mining tax," Mr D'Ascenzo said. He said the Tax Office was drawing on a senior group of people who had been close to the development of the tax.

"My role is to manage resources sensibly so that where there are priorities such as a new tax measure that's part of the government's framework ... we allocate from our scarce resources sufficient resources to handle that as well as we can," he said.

How companies value their assets loomed as the key flashpoint with industry, he said. "So we've been working with the mining companies as to possible valuation methodologies. It's quite a complex area in the whole mining game."

Drafts of valuation models preferred by the Tax Office were already circulating, he said.

"What we've been trying to do is provide some principles and then hope that commonsense applies in the way that they are used."