Fiji's SDL Party says the military government's decision to amend the constitutional process is unacceptable.
Last week, the president and interim prime minister announced that they dumped the draft constitution drawn up by the Constitution Commission, and will be replacing it with a new one by the end of the month.
The SDL says the regime claim that the Commission neglected fundamental principles is an insult to the intelligence of the men and women who followed the Commission's work.
A Constituent Assembly is to be set up by the interim prime minister next month to finalise the document.
However, the SDL says it will not participate in rubber stamping of any self-serving interest of a small group.
Meanwhile, the interim attorney general, Aiyaz Sayed-Khaiyum, has defended the changes, saying everyone needs to respect the President's decision in setting in place a process regarding the constitution.
He has told the Fiji Times that the aim is to produce a constitution that is not politically point-scoring and not a negotiated settlement.