Zimbabwe's unity government has failed during its four-year tenure to carry out key reforms to guarantee upcoming elections will be fair and violence free, an opposition leader said Wednesday.

"The people of Zimbabwe continue to be fearful everyday, we live in fear. All of us," said Simba Makoni, a former finance minister under President Robert Mugabe.

"The highest priority of national action must be to eliminate or remove that fear."

In perhaps the strongest criticism of the Mugabe-Tsvangirai power-sharing government by a senior Zimbabwean politician, Makoni described the unity government as "pathetic" and "dismal".

"Among all the high issues that will make up conditions to free and fair elections none of them has been implemented, not a single one of them," said Makoni.

The 63-year-old Makoni, who came third in 2008 elections with 8.3 percent of the vote, urged Mugabe's opponents to forge a "coalition" to unseat the long-time ruler, who has been in office for 33 years, since Zimbabwe gained independence.

"We want to work for a grand coalition of change," Makoni said.

"By committing ourselves to working with others, we are committing ourselves to support the most competent, the most eligible (candidate) for the office that is open."

Makoni thinks Mugabe, at 89, stands a slim chance of winning the election.

"Mugabe was not electable in 2008, I don't see how he can be electable in 2013," he said. "I know Mugabe fears losing his position."

Makoni, a former member of ZANU-PF's politburo, the party's supreme decision making body, formed his Mavambo Kusile Dawn party after ditching Mugabe in 2008.

Mugabe has labelled him a "prostitute" of the West and a "bloated frog".