"I am deeply, deeply distressed that we should be found not on the side of the ones who are suffering. I certainly am ashamed of what they've done in the United Nations,” the retired archbishop of Cape Town and Nobel Peace Prize laureate told BBC Radio 4.
"For the world to say no, we are waiting for South Africa's membership of the Security Council to lapse and then we can take action."
Archbishop Tutu said that his native South Africa’s inaction had betrayed its apartheid legacy.
"We should have been the ones who for a very long time occupied the moral high ground. I'm afraid we have betrayed our legacy."
The Archbishop repeated a recent call to the international community to remove Mugabe by force if he refused to step down voluntarily.
"He must be asked to step down, and if he refuses I really believe that we have to invoke this new doctrine of responsibility to protect," Tutu told BBC radio.
Asked whether that meant using force, Tutu replied: "Yes, yes - or certainly the threat of it ... He needs to be warned and his cronies must be warned that the world is not just going to sit by and do nothing."
In a letter to The Times this week, Foreign Secretary David Miliband said that Mugabe was a “stain” on Zimbabwe who could not remain in power if the country was to recover from its present crisis.
"If Zimbabwe is to haul itself - with the help it needs and deserves - out of its current meltdown, Mugabe has to go,” he wrote.
“As long as Mugabe rules Zimbabwe he remains a stain on that country.
“I acknowledge he is also a stain on the international community, which has not been able to deliver the will of the Zimbabwean people."
He stressed the role of neighbouring countries in taking action.
“It is obvious to everyone that neighbouring states, especially South Africa, have most to lose from instability in Zimbabwe and most to gain from change. That is why we continue to emphasise their role and responsibilities and to urge them to take action.”
Christian charities, including Tearfund, Christian Aid and World Vision, are working with partners on the ground to help Zimbabweans facing a cholera epidemic that has killed at least 1,000 people, and severe shortages of food, medicine and clean water.
