The Foreign and Commonwealth Office (FCO) issued the guidance in the early hours of Wednesday morning following political tensions in the African country.
President Robert Mugabe fired his deputy Emmerson Mnangagwa last week, with the 93-year-old leader having previously accused Mr Mnangagwa of plotting to oust him.
It has been reported the army commander has threatened to “step in” to calm political tensions and the sight of tanks in Harare has led to suggestions of a rift between the military and President.
Army tanks wait just outside of Zimbabwe capital
The FCO guidance said: “Due to the uncertain political situation in Harare, including reports of unusual military activity, we recommend British nationals currently in Harare to remain safely at home or in their accommodation until the situation becomes clearer.”