He also alleged the government of Laisenia Qarase had favoured the indigenous majority over the ethnic Indian minority.
Clark said the report clearly stated that democratic government was needed in Fiji following the coup.
"The report is clear the coup was not constitutional. It does call on the military to return to barracks and to see a civilian prime minister put in place."
"A lot of people seem to forget that 5 December was a takeover of a government and it was done by the military"
Frank Bainimarama, Fiji's prime minister and leader of last December's military coup
The eminent persons group was led by Sato Kilman, Vanuatu's deputy prime minister.
The other members of the group included Faumuina Luiga, Samoa's environment minister, Sir Arnold Amet, Papua New Guinea's retired chief justice, and Peter Cosgrove, a retired Australian defence force chief.
The report has not yet been made public and is due to go before a meeting of the Pacific Islands Forum foreign ministers, possibly to be held in Papua New Guinea in March.
In a recent interview with Al Jazeera, Bainimarama spoke of what lay ahead for Fiji following its fourth coup.
"It's been challenging - there's definitely a lot of work that needs to be done, but I'm getting a lot of assistance from the interim government ministers and of course the many people that come in to advise me on what to do," he said.
Bainimarama also defended Fiji's military against allegations of human rights abuses.
"A lot of people seem to forget that 5 December was a takeover of a government and it was done by the military," he told Al Jazeera correspondent Dan Nolan.
"The military needs to put in place scenarios that would stop any threat from being thrown in our direction," he said.