The survey of 2435 women and 2092 men, carried out by the National Centre for Violence and Traumatic Stress Studies (NKVTS), found that 9.4 percent of women in the country reported having been raped, compared with 1.1 percent of men.
"These is very serious information, and the dark figures presented here are much larger than what we've seen in public statistics," Anders Anundsen, Norway's Justice Minister, told the VG newspaper.
"What concerns me, as well as the scale, is that so few come forward. They decide to keep it to themselves, rather than take advantage of the support system that exists."
According to the survey, 49 percent of the women who reported being raped said that the attack had taken place before they were 18 years old, with the perpetrator most likely to be a known person such as a friend, acquaintance, neighbour, work colleague, boyfriend or ex-boyfriend.
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Only eleven percent of those who had been raped reported it or underwent any medical examination, with a third of victims never telling anyone what happened.
"One of the reasons why so few choose to report is that victims say that it is no use," Ole Kristian Hjemdal from NKVTS told VG. "It's a hidden problem."