The index showed that they perceived their financial situation in the first quarter of this year to be mildly exposed to risk factors, leaving them unable to cope financially.
The CFVI declined to 50.2 points in the first three months of this year, from 52 points in the last quarter of 2013.
MBD provides credit management solutions. The CFVI analysis of consumers' perceptions of cash flow was conducted by Unisa's Bureau of Market Research (BMR) on behalf of MBD.
The analysis looked at income, expenditure, savings and debt servicing sub-components. A significant decline in the debt servicing sub-component was the main reason for the decline in the overall index.
Analysis showed that consumers were becoming less able to service their debt because of insufficient income.
The drop in income was caused by higher expenditure, as a result of inflation, and larger debt repayments caused by the interest rate hike.
"It is especially the low to middle income groups whose debt servicing ability were affected most, given that they have to service more expensive debt."
However, BMR Prof Bernadene de Clercq said consumers' savings improved marginally in the first quarter of this year.