Zimbabwe's government has rejected accusations that it is failing to meet its democratic obligations in the run up to elections on 29 March.
President Mugabe has been campaigning across the country
US-based Human Rights Watch (HRW) said that the government had intimidated opposition supporters, and that the electoral process was deeply flawed.
But Deputy Information Minister Bright Matonga told the BBC such reports reflected what the West wanted to hear.
He said Zimbabwe's electoral commission was adequately prepared and unbiased.
"The Zimbabwe Electoral Commission (ZEC) is comprised of persons from the ruling Zanu-PF and the opposition MDC," he told the BBC's Focus on Africa programme.
"You can't make a prejudgement on something that has not been proved wrong," he said, adding that the government was "very happy" with arrangements so far.
The ZEC has announced that 5,934,768 people have registered to vote in 8,998 polling stations.
The opposition say they have found evidence of dead people registered to vote including a former minister who died 30 years ago.
They have gone to court seeking an electronic copy of the register to allow computerised searches and the easier detection of any fraud.
President Robert Mugabe's main challengers in the presidential polls are the opposition Movement for Democratic Change's Morgan Tsvangirai and former Finance Minister Simba Makoni.
Mr Matonga accused HRW of having an agenda in compiling the report.
"We are not surprised at all by these kind of reports, actually they are becoming a joke," he said.
"The organisation that is doing that - they should be ashamed of themselves because they don't see anything positive about Zimbabwe. That report was compiled by people who are not Zimbabweans , who don't live in Zimbabwe, who got an agenda with the observers."
But the Zimbabwe Election Support Network has said the distribution of polling stations have been biased in favour of rural areas where Mr Mugabe has more support.
In the past, the government has pointed to a series of new laws designed to deal with electoral criticisms.
But HRW says those laws have either come too late to make any difference, or been selectively applied.
It accuses the security forces of intimidating and torturing opposition supporters, and state media of blatantly biased election coverage.
"Despite some improvements on paper to the election regulations, Zimbabweans aren't free to vote for the candidates of their choice," said HRW.
HAVE YOUR SAY
Such a pity for the food bowl of Africa to turn into a pauper state.
Vish Viswanathan, NZ
The report concludes that there is little chance that the polls will either establish democracy in Zimbabwe, or bring an end to the country's ongoing political crisis.
Observers say administrative preparations for the polls are also being severely hampered by the nation's deepening economic crisis, with inflation running at more than 100,000% and shortages of fuel and basic foodstuffs.