Finance Minister Tendai Biti announced on Thursday that growth projections for the current year had to be reduced and inflation figures revised higher, mainly because diamonds did not produce as much income as had been expected.
Last year Biti predicted that revenue from mining and agriculture would help the country's economy to grow by over 9 per cent in 2012.
But in his quarterly economic update, the Finance Minister told reporters the economy had experienced a difficult period in the first quarter of the year, with diamonds bringing less revenue than he had predicted.
It was revealed that the stones from the Marange alluvial fields accounted for $30.5-million of revenue in the first quarter of 2012. A target $123-million had been set by government.
The Minister used the word "opaqueness" in reference to diamond sale activity, alluding to what many Zimbabweans call "the lack of transparency" which the Mugabe regime has maintained regarding the sale of the precious stones.
In the past Biti himself has admitted that the government is being prejudiced of millions of dollars in diamond revenue, which does not make it into government coffers.
The country's total revenue for the first three months of 2012 was $771 million, far below the government target of $870-million. Minister Biti also attributed the decline to a general decline in global demand for minerals, which bring in the bulk of Zimbabwe's export income.