Health Ministry spokesman W.M.D Wanninayaka said that over 10,000 people have been affected by dengue so far this year.
He said that the number of people affected by dengue during the first three months of this year alone was higher than the figure seen during the same period last year.
As a result the Health Ministry today declared 25 administrative divisions in the country including the capital Colombo as high risk areas for contracting dengue.
Wanninayaka said that health authorities expect a steep rise in the number of people affected by dengue over the next two months.
Health Minister Maithripala Sirisena met officials in Colombo on Friday to discuss concerns over the spread of dengue and the measures to be taken to eradicate dengue mosquito breeding grounds around the country.
Over the first three months of 2011 Sri Lanka 3088 people were affected by dengue but that figure has risen to 9412 during the first three months of this year, the Health Ministry said.
Wanninayaka said that as of last week the figure for this year stood at 10048 with 46 deaths.
The Health Ministry also found that students in Colombo faced the risk of contracting dengue as the April school vacation drew to a close.
Areas around some city Schools which remained closed for the vacation were not cleaned and the authorities said they had found several dengue mosquito breeding grounds.
The authorities had also found that over 100 bare lands in the capital had also become mosquito breeding grounds and so legal action is to be filed against the land owners.