Dr Palitha Maheepala, a top health ministry official said that there have been 11,795 dengue patients during the first five months of this year.
There were 74 deaths during this period.
Some 76 per cent of the dead have come from the age category of 15 to 50 and above.
24 per cent accounted for in the age category 5 to 15, health officials said.
Alarms have been raised since the deaths of children of two corporate business leaders last week.
The densely populated western province has provided the most number of patients.
The capital district of Colombo has recorded the most number of patients 2,976 with 24 deaths.
The surge in the number of cases came despite a national programme for dengue eradication launched in 2010.
People have been warned not to neglect treatment by obtaining prompt medical care.
Sri Lanka is a category-A country designated by the World Health Organization which means dengue fever is a leading cause of hospitalisation and death among children.