Some 6,000 more people died between February 6 and March 18 this in comparison to the same period in 2011.
The InVS have not given offered an official explanation for this increase, but it is thought to be a result of a cold snap over the same period and seasonal illnesses.
Anne Fouille, the statician behind the study, said the simultaneous occurrence of several factors in February and March, including unusually low temperatures and bouts of illnesses “could explain this phenomenon, at least in part.”
Between February 1 and 13 there was an exceptionally cold spell across the country, with the north suffering the most with temperatures of minus 18 degrees.
At the same time an epidemic of gastroenteritis hit, followed by an epidemic of seasonal flu, which hit a peak at the beginning of March.
Elderly people were particularly affected, with an 18 percent rise in deaths among the over-85s and a 31 percent rise for the over-95s.