The funds will be made available to "critical" industries including food processing and fertiliser companies, he told Reuters during a visit to London.
"COMESA (Common Market for Eastern and Southern Africa) has provided a line of credit and so have Botswana and South Africa and that brings the line of credit to $400 million," Biti said.
"Botswana is giving us $70 million and South Africa is giving us $50 million and COMESA is giving us the bulk of the amount."
State media reported on Wednesday that the southern African country had secured $400 million in credit lines to help the local economy recover from years of economic contraction and hyper-inflation.
A unity government formed by rivals President Robert Mugabe and Prime Minister Morgan Tsvangirai has appealed for billions of dollars from the West.
Asked when Zimbabwe was expecting aid from Western governments, Biti said it would come "soon".
Western donors, who are expected to provide the bulk of funding for Zimbabwe’s economic recovery, have demanded broad economic and political reforms, including ending a new wave of farm invasions targeting the few remaining white farmers.