Public sector pay rises have also been outstripping the private sector.
Others said base salary movements varied and depended on skills and competition for talent.
Official figures put public servant adjusted salary and wage rises in the year to June 30 at 3.7 per cent.
But unadjusted figures - considered the best indicator of "take-home pay" - were as high as 5.5 per cent for the public and private sectors combined.
Former Prime Minister Helen Clark was paid a salary of $375,000 over the past year, and her deputy Michael Cullen got $264,500.
As both have moved out of leadership roles and on to the Opposition benches, their pay will tumble to near $130,000 even when the new rise is taken into account.
Mr Key will get the rise added to the existing Prime Minister's salary of $375,000. His salary as Leader of the Opposition was $233,000.
Mr Key is a multimillionaire after a career in the financial world and gives most of his political salary to charities.
He has said he intends to continue doing that with the bigger pay packet.
The biggest winners are the National MPs who have gone from Opposition seats to Cabinet positions.
Among them are Gerry Brownlee, Simon Power, Judith Collins, Tony Ryall, Anne Tolley and Paula Bennett.
Their salaries will go from around $130,000 to near $240,000.
Ministers outside the Cabinet - who include United Future's Peter Dunne, Act's Rodney Hide and Heather Roy and Maori Party co-leaders Tariana Turia and Pita Sharples - get almost $200,000.
New Labour Party leader Phil Goff gets the same money for being Leader of the Opposition as he got for being a Cabinet minister.
As well as getting more money for becoming ministers, John Key's new team get expense allowances and the use of a fleet of silver BMW limousines.
WHAT THEY GET
John Key
* Before the election $233,000
* Yesterday $375,000
* From today $393,000
Helen Clark
* Before the election $375,000
* Yesterday $126,000
* From today $130,000
TOP POLITICIANS' PAY OVERSEAS
Australia
* PM A$330,000 ($388,000)
* Cabinet ministers A$219,000 ($258,000)
* Leader of the opposition A$235,000 ($277,000)
* MP A$127,000 ($149,000)
UK
* Prime Minister £189,000 ($514,000)
* Cabinet minister £138,000 ($375,000)
* Leader of the Opposition £131,000 ($356,000)
* MP £62,000 ($169,000)
US
* President US$400,000 ($728,000)
* Senate minority and majority leaders US $188,000 ($342,000)
* Senator US$169,000 ($308,000)