Federal government departments spent nearly half a billion dollars on travel and accommodation in 2016, equivalent to more than $2700 for each of the nation's 155,000 public servants.
Department of Finance figures show the bill for the whole of government travel system totalled $427 million last year, including bookings of domestic and international flights, hotels and car rentals.
The travel bill has grown by as much as $50 million since the 2013-14 financial year, when domestic flights made up 65 per cent of the $377 million spent.
The following year, the government booked travel across 1.4 million sectors, costing about $420 million.
The figures don't include some travel costs by government owned businesses.
As part of the spending, the Department of Foreign Affairs and Trade told Senate estimates travel booked with departmental corporate credit cards in 2015-16 totalled $4.64 million, up from $3.35 million the previous year.
The top domestic routes flown by government travellers include Sydney-Canberra, Melbourne-Canberra and Canberra-Brisbane. Internationally, the top routes include Perth-Christmas Island, Sydney-Los Angeles and Sydney-Singapore.
Governments have previously declined to release the total amount spent on travel as part of the centralised arrangements for non-corporate Commonwealth entities, with the bill to taxpayers estimated at about $500 million in 2012.
Established in July 2010, the government-wide system is designed to reduce costs and simplify some booking and administration processes. It makes the federal government the largest air travel user in Australia, ahead of BHP Billiton, Rio Tinto, large consulting firms and the big four banks.
Administered by Finance, the system permits bureaucrats and officials to buy the lowest practical airline fare - the cheapest ticket that suits the "practical business needs of the traveller". Public servants are required to book semi-flexible economy seats, unless they are entitled to business class travel or are given specific approval to upgrade.
For overseas travel, the best international fare must be selected from at least three quotes with public servants required to apply "an appropriate level of rigor" in finding value for money.
Amid ongoing cost saving drives, governments from both sides of politics have required public servants to reconsider their need to travel for work and to use video conferencing and other technology as much as possible.
Official guidelines tell public servants to "book like a private traveller", seeking cheaper, less flexible fares wherever possible an not to seek out specific aircraft or full-service airlines.
Public servants must not consider access to airline lounges or status credits among reasons for choosing fares. Tickets in the system do not attract frequent flyer points.
Carriers including in the latest system, announced last year, include Qantas, Virgin, Jetstar, Regional Express, Air New Zealand, British Airways, Cathay Pacific, Emirates, Air Niugini, Etihad and Singapore Airlines.
A new panel of 18 airlines allows for competitive fares and discounts for departments and federal agencies, delivering savings over market fares as well as some flexible conditions for government travellers.
The government also negotiated some simplified contract management provisions and receives reports on travel patterns.