The daily allowance has been increased from £330 to £420, while the time commitment has remained unchanged at 30 to 50 days in the first year and "a lower daily commitment anticipated in subsequent years".
The closing date for applications is 18 August with interviews scheduled for 29 August.
APPC chairman Iain Anderson expressed concern about the length of time the search is taking.
"The timescale is now getting tight for the implementation of the register before the General Election," he said.
"It is important there is time for proper consultation on the format and the costs of the register as well the Registrar's view on many key issues."