Sri Lanka raised rates and increased energy prices in February after the exchange rate came under pressure from high credit growth particularly by state energy enterprises which were manipulating prices.
The Central Bank said in April private credit fell to 18.7 billion rupees. However credit to state was over 40 billion rupees in the same month.
Imports fell 3.3 percent in April.
"The cumulative trade data for the first four months of 2012 indicate that imports are decelerating at a rapid pace in line with the policy measures adopted," the Central Bank said.
"However, notwithstanding the incentives provided for exports as a result of the policy measures, exports too have declined year-on-year, due to global developments."
A contraction in trade is an indicator of a slowdown in domestic economic activity.
The Central Bank said it was maintaining a 7.2 percent growth forecast for 2012 with first quarter indicating strong growth though the pace may slow in subsequent months.
Export had fallen despite a steep depreciation of the rupee over the past year from 109 to 131 to the US dollar.
Inflation rose to 7.0 percent in May, as the exchange rate fell.
On Tuesday the rupee fell to a new low of 133.60 to the US dollar.