Addressing the annual conference of his ruling ZANU-PF party on Friday, Mugabe made clear he was displeased with remarks made by UN Under Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Jan Egeland, who paid a three-day visit to Zimbabwe this week and met victims of a recent demolitions campaign.
"He tells lies, utter lies," Mugabe declared. "It's a damn hypocrisy and a lie."
Egeland ended his mission to Harare and Bulawayo on Wednesday warning that "the humanitarian situation in Zimbabwe is very serious".
"The prospects are worrying. The need for international assistance is big and growing. The people of Zimbabwe are suffering under several big problems," he told a news conference in Johannesburg.
Zimbabwe better off
Mugabe said that Zimbabwe was better off than other countries on the continent.
Mugabe says Zimbabwe is better
off than other African countries
The 81-year-old president said he would tell UN Secretary General Kofi Annan "not to send men or women who are not his own but the agents of the British because we don't trust men and women from his office anymore."
During talks with Egeland, Mugabe refused a UN aid offer of tents to shelter the hundreds of thousands of victims of the urban demolition campaign, saying he would only accept assistance to build permanent housing.
Zimbabwe police and recruits used bulldozers and sledgehammers to demolish shacks, homes, market stalls and small business in poor areas across the country during what was dubbed Operation Murambatsvina, or Drive Out Trash.
The operation that began in May and was declared over in July left more than 700,000 homeless or without livelihoods, or both, according to UN estimates, that the government has rejected as an exaggeration.
Tsvangirai has lead the MDC
In a separate development a Zimbabwe court on Friday dismissed a case brought by members of the country's main opposition party seeking to oust party leader Morgan Tsvangirai.
The Movement for Democratic Change (MDC), which has posed the biggest challenge to Mugabe's 25-year rule, has been in turmoil since it split into two factions in a disagreement over participation in last month's Senate polls.
Tsvangirai told a news briefing on Friday the court result would bring the party back as a political force.
"If Robert Mugabe thought he had an early Christmas present of a dead MDC, he shall now get a New Year wake-up call," said Tsvangirai.
The MDC dispute arose after Tsvangirai, who has led the party since its founding in 1999, called for a poll boycott. He argued that participating in the vote would give credence to an election he said was rigged to produce victory for Mugabe's ruling ZANU-PF.