Speaking at his Zanu-PF party's annual conference in the eastern city of Mutare, Mugabe vowed to fight sanctions imposed on him and party leaders, the BBC reported.
Mugabe also said he wants to end power-sharing with the party of Prime Minister Morgan Tsvangirai, and that he will push for elections early next year. More than 4,000 Zanu-PF members attended the conference.
"Why should we continue to have 400 British companies operating here freely?" Mugabe said.
"Why should we continue having companies and organizations that are supported by Britain and America without hitting back? Time has come for us to (take) revenge. We can read the riot act and say this is 51 percent we are taking and if the sanctions persist we are taking over 100 percent," Mugabe said."
Under Zimbabwe's empowerment laws, black Zimbabweans should acquire 51 percent of foreign businesses.