Remittances by Zimbabweans abroad through official money transfer agencies and banks declined by 15 percent from US$2.1 billion in 2012 to US$1.8 billion, according to the Reserve Bank of Zimbabwe.
But the central bank pointed out that a considerable amount of diaspora remittances continued to be transmitted through unofficial channels.
Although the central bank did not say so, informal channels dominate transfers from South Africa where the bulk of Zimbabweans who have left the country reside.
Couriers popularly known as malaisha are doing a roaring business of transporting goods, cash and people.
Drivers of cross-border buses also earn a lot of extra income by carrying cash from Zimbabweans in South Africa to their relatives in Zimbabwe.
The central bank said it was looking at ways to tap into the diaspora resources, guided by the 2014 national budget.