The Fiji-based Pacific Centre for Public Integrity says the Police Commissioner and Director of Public Prosecutions should keep their independence.
The PCPI says such positions are established under the constitution.
The call comes after the Police Commissioner voiced concerns that budgetary control for his department had been given to the ministry of home affairs.
The Commissioner said anyone controlling the budget of an organisation, in essence controls that organisation.
The PCPI director, Angie Heffernan, says the Constitutional Offices Commission needs to enact policies that protect the independence of positions like Police Commissioner.
"These are National Integrity Institutions, established under the constitution. You need to actually deal with them quite separately from the normal sort of state bodies, basically to make sure that they are able to be independent and they are able to operate with integrity as well. They are able to fulfill their constitutional mandate without fear of political interference."
Meanwhile the Police Commissioner, Andrew Hughes says he is ready to start a legal challenge against the recent budget changes if the need arises