Fiji has been shaken by four coups in the past 35 years, and the possibility of military intervention loomed over a tight general election last month.

Rabuka's victory ended the 16-year rule of former naval commodore Frank Bainimarama, who seized control of the Pacific archipelago through a putsch in 2006.

Under Fiji's constitution -- adopted in 2013 -- the military has wide powers to intervene in politics.

Rabuka's government has said that reviewing the constitution is one of its immediate priorities.

In a statement "authorised" by Major General Jone Kalouniwai, the Republic of Fiji Military Forces (RFMF) said it had "growing concern" over the ambition and speed of the government's "sweeping changes".

The military worries that the changes are being pursued "without full understanding" of procedures or are being "intentionally done to challenge the integrity of the Law and the Constitution of this land", Kalouniwai said.

Hours after issuing the statement, however, he said the military would continue to "honour the current government that is in place".

"Let me just reassure the public that the RFMF will continue to stand with democracy, we will continue to respect the law," Kalouniwai told online news outlet fijivillage.com.

The military chief did not single out any specific government reform for criticism.

Besides the touted constitutional review, Rabuka has said that the government plans to set up a "mercy commission" to decide on possible presidential pardons or reduced sentences for convicts.

The prime minister has rejected media suggestions that the commission is aimed at pardoning George Speight, a bankrupt businessman serving a life sentence after leading a coup in 2000.