Salaries are currently based on previous earnings and ministers are concerned that advisers, and their aspirant Labour opposite numbers, are seeking employment away from Westminster in the hope of returning with a larger income.
The inquiry, being conducted by Roger Freeman, Chancellor of the Duchy of Lancaster, will focus on the huge disparity in earnings for the group, most of whom perform the same job.
The role of political adviser, devised by Labour in the 1960s, invests the status of civil servants on a number of ministerial aides who perform overtly political functions. Those recruited from the private sector - usually lobbying, the City or law - often earn twice as much as those who took the job after working in Conservative Central Office, the favoured recruiting ground.
This fact has not been lost on a number of Labour researchers who might expect - assuming Tony Blair wins the next election - to be on the political adviser payroll by this time next year. A number of Labour researchers from Parliament and John Smith House (who are lucky to earn pounds 25,000 per annum), have recently left for the private sector where the norm would be more than pounds 40,000 plus car and private health insurance. Recent departures include Jack Straw's researcher Ben Lucas, who now works for lobbyists Lowe Bell.
According to the last available figures there are 39 political advisers, including technical experts advising departments like the Treasury and Environment, and members of the Downing Street policy unit.
All, with the exception of the Head of the Downing Street Policy Unit, Norman Blackwell, are on the pay "spine" of more than 30 points, ranging from pounds 20,631 to pounds 71,517. Mr Blackwell earns more than pounds 71,517.
The political adviser role, with access to ministerial meetings and to Cabinet papers, presents an ideal opportunity for young, aspiring politicians to cut their teeth. But Michael McManus, former adviser to David Hunt (and now an aide to Sir Edward Heath), argued: "It is curious to have people doing more or less the same job on such a disparity of salary. There is a great incentive, if you come the Conservative Central Office route, to move on quickly."