In a briefing to the U.N. Security Council that British Foreign Secretary David Miliband called "devastating," Ban said the failure to form a government since March elections has been accompanied by a dramatic deterioration in living conditions.
Ban said 5.8 million people, more than half the population, would need food aid in the months through to March, and nine out of 10 provinces had reported cholera cases in one of the worst epidemics in Zimbabwe’s history.
President Robert Mugabe lost the first round of presidential elections in March to opposition leader Morgan Tsvangirai, but Tsvangirai withdrew from a run-off citing attacks on his supporters. The two reached a power-sharing agreement in September but have yet to form a government.
Miliband said the political impasse was caused by Mugabe’s refusal to implement the September agreement and that while the disease in the headlines now was cholera, the heart of the problem was "the disease of misrule and corruption."
The cholera epidemic and Zimbabwe’s economic meltdown have drawn new calls from Mugabe’s Western foes for the resignation of the 84-year-old leader, who has ruled since independence in 1980. Mugabe has accused Western countries of trying to use the cholera outbreak to force him out of power.
"There is still denial of the gravity of the humanitarian situation in the country and the collapse of state structures," Ban said in his report to the council.
He said the international community must insist on the immediate formation of a government of national unity.
The Southern African Development Community has taken the lead on mediations which have been conducted on its behalf by former South African President Thabo Mbeki.
Ban said SADC’s mediation needed fast results.
"SADC leaders should display stronger unity and resolve to address the political stalemate," Ban said, adding that while he was ready to help wherever possible, neither the government of Zimbabwe nor the mediator welcomed a U.N. role.
"This clearly limits our ability to effectively help find immediate remedies to the crisis," Ban said.
The Security Council met behind closed doors to hear Ban’s briefing and did not issue any statement or resolution on the crisis. Council member South Africa has resisted efforts to bring the Zimbabwe situation to the council, arguing that it is not a threat to international peace and security.