Environment minister Saviour Kasukuwere said the elephants had died in the past few weeks in the Hwange national park, the southern African nation's largest, while security forces were preoccupied with a July 31 general election.
Police and rangers had recovered 19 tusks, cyanide and wire snares after a sweep through villages close to the park, which lies just south of Victoria Falls.
Mr Kasukuwere said: "We are declaring war on the poachers. We are responding with all our might because our wildlife, including the elephants they are killing, are part of the natural resources and wealth that we want to benefit the people of Zimbabwe."
Zimbabwe is home to some of Africa's largest herds, with half of its estimated 80,000 elephants thought to be in Hwange.
Mr Kasukuwere said he would push for stiff penalties for convicted poachers who routinely get less than the nine-year jail term imposed for cattle rustling.