The man chosen to conduct the "functional and efficiency" review of the Australian Taxation Office, Phil Gaetjens, will be paid $167,000 for his services.

Another $620,000 will be paid to private sector consultants the Nous Group to support the work of Mr Gaetjens, former chief of staff to Howard government treasurer Peter Costello.

The figures have emerged as the ATO revealed that it hopes to strip tens of millions in allowances and entitlements from its workforce and reap nearly $30 million in boosted productivity each year by extending working hours for its public servants.

Contracts lodged with government website AusTender show that Mr Gaetjens, a key architect of the GST while running Mr Costello's office, will be paid $166,749 for his services.

The Nous group, private sector management consultants, who will act as secretariat to the review, will be paid $620,512.

The news comes as the Tax Office is pushing a proposed enterprise agreement for its workforce that is underpinned by $184 million in savings from reducing sickies among its public servants, having them work longer hours and "reinventing the ATO".

Another $184 million will be found in "affordability" initiatives, such as stripping workplace allowances and off-loading empty office space around Australia.

The Tax Office is giving little away publicly about the functional and efficiency review.

But stakeholder briefings have been told the office's hierarchy is thinking big and looking at the review as an opportunity to expand its activities.

The agency is also exploring ideas for collecting GST at the point of sale.

In April Mr Gaetjens finished a four-year stint  running the NSW Treasury.

The former public servant will be assisted by ATO deputy commissioner Sue Sinclair and assistant commissioner Debra Unsworth.

Possibilities canvassed include development of technology allowing reconciliation of GST at the point of sale, massively easing the regulatory burden on small and medium businesses particularly in the retail and hospitality sectors.

The ATO is also exploring the idea of acting as a service provider collecting revenue for other federal agencies. State governments are also in the mix, with Tax Office bosses eying opportunities to collect state-based charges like payroll tax.

As part of the 2015 budget, Finance Minister Mathias Cormann ordered all departments to carry out functional and efficiency reviews with some already completed and others underway.

Finance Department secretary Jane Halton told a function in Canberra this month that $200 million in potential savings had already been identified by reviews at the Health and Education departments.

Commissioner of Taxation Chris Jordan told his workers the review was  intended to "comprehensively assess the efficiency and effectiveness of all aspects" of ATO operations, programs and administration.
The review will be taking into account considerations from the Australian Public Service Commission's Capability Review and other relevant reviews.

Meetings have already been held between the ATO hierarchy and Mr Gaetjens to talk about the direction of the review.