THE Citizens Constitutional Forum claims the opposition leader will have a reduced role under the new Constitution compared to earlier constitutions.
In its analysis of the Constitution, the forum said the opposition leader's position was a critically important one in parliamentary executive systems.
"He or she has a vital role in ensuring Parliament keeps the executive accountable," the forum analysis said.
"Beyond that, the opposition leader is the alternative prime minister and as such is accorded considerable respect and given important roles in key institutions other than parliament.
"This is especially important in Fiji with its history of communal politics."
The CCF said in the 1997 Constitution, the Office of the Opposition Leader held a central role in appointments to the Senate, many of the independent commissions and offices, the Chief Justice and other judges.
It said the 2012 draft gave extensive powers to the opposition leader to control an early dissolution of parliament, make appointments and control the military through the National Security Council.
But, the CCF said, by taking away these powers from the opposition leader, the new Constitution "undermines the role of opposition parties in Parliament to balance the majority party".