"We will carry it on, till the government responds to the people."
In March 12-month inflation in Sri Lanka's capital hit 23.8 percent on a controversial new index from which an entire expenditure group has been dropped.
On an older index, inflation hit a historic high of 28.1 percent.
The usually sleepy UNP has attracted criticism as one of the weakest oppositions in the country's post-independence history.
Wickremesinghe says the government gave various excuses such as the oil prices for high inflation but that has now been refuted by even the International Monetary Fund.
"The latest IMF reports say, due to the printing of money the cost of living increased rapidly in 2007."
The IMF report said only a quarter of Sri Lanka's inflation in the past two years could be explained by 'external' factors such as oil, import