Presidential spokesperson George Charamba accused Western countries of seeking to bring Zimbabwe before the UN Security Council by claiming that a cholera epidemic and food shortages had incapacitated his government.
"The British and the Americans are dead set on bringing Zimbabwe back to the UN Security Council," he said in the government mouthpiece Herald newspaper.
"They are also dead set on ensuring that there is an invasion of Zimbabwe but without themselves carrying it out. In those circumstances, they will stop at nothing," he said.
"We would not be surprised if they spring a ‘mission’ involving the UN," he added.
EU nations on Monday upped the diplomatic pressure on the Zimbabwe government, broadening sanctions on Mugabe and his inner circle while French President Nicolas Sarkozy added his voice to the growing calls for the end of Mugabe’s rule.
Former colonial power Britain has led the international chorus calling for Mugabe to step down after a 28-year rule that has left the country’s economy in shambles amid a political deadlock after controversial elections earlier this year.
The United States as well as African countries like Botswana and Kenya have also said Mugabe should go, but most of Zimbabwe’s neighbours have remained silent or backed floundering negotiations aimed at forming a unity government.
A cholera epidemic that has claimed nearly 600 lives has overwhelmed Zimbabwe’s dilapidated hospitals, which have few drugs or equipment to treat patients.
Doctors say the death toll could be much higher, while the UN children’s agency Unicef has warned that 60 000 cholera cases could emerge in the coming weeks.
Zimbabwe has declared a national emergency and appealed for international aid to fight the disease.
Health minister David Parirenyatwa praised donors and non-government organisations for giving drugs and supplies, but said more help was still needed.
"Donors and NGOs have also responded positively although the assistance is not enough and we still need more," he said in the Herald.
The country also faces crippling shortages of food, with nearly half the population expected to need emergency aid next month, according to the United Nations.
The once-vibrant economy has been shrinking for nearly a decade, and is now hammered by the world’s highest inflation, last estimated at 231 million percent in July.