Foreign Minister Murray McCully says Fiji has taken a backward step by "trashing" a new draft constitution.
Fiji President Ratu Epeli Nailatikau said on Thursday that the draft prepared by a commission led by Kenyan academic Professor Yash Ghai risked reigniting racial tensions and undoing reforms introduced by Prime Minister Frank Bainimarama.
The military regime has given its legal team until the end of the month to produce a new draft that will be debated by a constituent assembly.
Mr McCully said it was unhelpful that the commission's work had been trashed and the international community would be watching to see what the constituent assembly does and whether the proposed 2014 elections will be "free and fair".
Downgrading the role of the military would be a challenge, he told Radio New Zealand.
"This is not flash. It's a backward step of some proportions," Mr McCully said.
"But it's been the history of this whole process. This is not going to be a simple straight line towards elections and international credibility."
The Fiji Island Council of Trade Unions is urging people to boycott the constituent assembly following the dumping of Prof Ghai's draft constitution.
General Secretary Attar Singh said in a statement that the assembly "will now do no more than to rubber stamp the regime's constitution".