Tax Commissioner Chris Jordan will get another seven years at the head of the Australian Taxation Office, with the agency looking to hit more multinationals with another $4 billion in tax bills.

The tax assessments come off the back of $2.9 billion in tax liabilities against seven multinational companies.

Mr Jordan was appointed in the top job by former Treasurer Wayne Swan in January 2013. In an unprecedented move, Treasurer Scott Morrison announced the reappointment two years ahead of the Commissioner's term expiring.

Ramez Katf, who is currently Chief Information Officer and has been handling the ATO's controversial IT changes, has been appointed as Second Commissioner of Taxation.

"Mr Jordan's term as Commissioner of Taxation, and Registrar of the Australian Business Register, which had been slated to conclude at the end of 2019, will now run until February 29, 2024," Mr Morrison said.

"Mr Katf's term will run from 1 May 2017 to April 30, 2024."

Mr Morrison said Mr Jordan had shown "strong leadership in working with the government to implement its strong multinational tax avoidance laws". 

The ATO had a big win against oi giant Chevron in the Federal Court last week, when the Full Federal Court unanimously decided that the company had to back pay about $300 million in taxes. The long-running dispute was initiated under previous tax commissioner Michael D'Ascenzo.

Mr Morrison said ATO has advised that it expects to raise more than $4 billion in additional tax liabilities this year from large public groups and multinationals.

The hunt for greater revenue from multinationals is no certainty, as it's unclear whether companies will fight the ATO in court, or the tax man will cut deals with large businesses as it has historically done.

Nevertheless, Mr Morrison said: "With the Government's support and additional funding, it is clear the ATO is delivering real results under Mr Jordan's leadership of the tax office."

He said Mr Katf "has extensive experience in driving and implementing transformational change in large organisations". 

"As Second Commissioner, Mr Katf will maintain the CIO role and continue to focus on modernising the revenue collection system and contributing to the government's broader digital agenda," Mr Morrison said.

Aside from Mr Jordan and Mr Kaft, the ATO executive team also consists of Chief Operating Officer, Jacqui Curtis, Chief Service Delivery Officer, Melinda Smith,  Chief Finance Officer, Frances Cawthra, Second Commissioner Neil Olesen, and Second Commissioner Andrew Mills.

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