THE millionaire businesswoman and former prime minister's wife Therese Rein has been the biggest beneficiary of free flight upgrades from Qantas, the country's most generous provider of largesse to federal parliamentarians.
Ms Rein's haul of 22 domestic and international flight upgrades puts her ahead of much-upgraded politicians including the former speaker Peter Slipper with 15 (including five for his spouse) and the former Tasmanian senator Nick Sherry on 14.
Ms Rein's husband, Kevin Rudd, finishes a lowly sixth with eight upgrades - although in total he discloses 31 upgrades including one for a child.
A Herald investigation found politicians recorded 289 upgrades over the two-year period, more than 200 handed out by Qantas to a value of hundreds of thousands of dollars.
An upgrade from business class to first class represents an extra bill of about $6000 on a return trip to Frankfurt.
Ms Rein's reign as queen of the upgrades, largely from Qantas, occurred during Mr Rudd's tenure as minister for foreign affairs.
However, a spokeswoman for Ms Rein said they related to her travels as a businesswoman for her recruitment company Ingeus.
''As managing director of the international Ingeus group of companies Ms Rein travels very frequently, resulting in a greater quantity of upgrades,'' she said.
The upgrades are additional to free membership of Qantas's Chairman's Lounge given to all 226 serving politicians - allowing them privacy and free food at most domestic airports.
Then there is Qantas's supply of iPads and tickets to the AFL grand final - enjoyed in 2010 by Bill Shorten and Martin Ferguson - and the Australian Grand Prix enjoyed by Stephen Conroy (last year) and Joshua Frydenberg (this year).
Eleven politicians disclosed they had received an iPad from Qantas, only three saying they would donate the gift to charity or pay for it above the limit of $750 on politicians' gifts.
Revelations about Qantas's gift giving come after the Qantas chief executive, Alan Joyce, launched a lobbying offensive claiming the national carrier faced unfair ownership restrictions due to a cap on foreign equity.
Mr Joyce personally lobbied several politicians in Canberra about the restriction, which caps foreign ownership at 49 per cent of the Australian carrier and is seen as a barrier to enticing interest in Qantas from other major airlines.
In terms of spending power on politicians' upgrades, the investigation shows Qantas is leagues ahead of its rivals, with 206 upgrades attributed to Qantas, 17 to Emirates and seven to Etihad.
Only one upgrade was attributed to Qantas's domestic arch rival, Virgin Australia.
A spokeswoman for Qantas would not say how much its campaign of wooing politicians cost, or explain why the airline was interested in providing extras to politicians.
''The Qantas Chairman's Lounge is by invitation only. These memberships are at the discretion of the airline,'' the spokeswoman wrote in response to Herald questions.
''Privacy laws prevent us from discussing individual memberships.''
The expensive charm offensive turned on for politicians is not reflected in a reciprocal love affair. Only two parliamentarians, the Kalgoorlie MP Barry Haase and Queensland MP Peter Dutton, list Qantas among their shareholdings - less than 1 per cent of federal politicians.
And finally, MPs Chris Hayes and Kelly O'Dwyer reported they had received ''involuntary'' or ''not requested'' upgrades to business class on international flights.