About one in ten admitted to raping a woman who was not their partner. When partners were included, that number rose to 24 percent.
Rape was most prevalent in Papua New Guinea, where 60.7 percent of men surveyed admitted forcing a woman to have sex.
In Cambodia, China and Indonesia rape prevalence varied widely between regions and ranged from one in five to almost half of all men surveyed.
The lowest prevalence was urban areas of Bangladesh with just under 1 in 10 men admitting rape, and Sri Lanka with just over 1 in 10.
Published in two separate studies in the journal Lancet, the research is from Partners for Prevention -- a coalition of four U.N. agencies addressing gender-based violence in the region -- and includes the reasons why men say they rape.
The most common reason, given by 73 percent of respondents, was "sexual entitlement," which factors especially into those who raped their partners. "They believed they had the right to have sex with the woman regardless of consent," said report author Dr. Emma Fulu.
Rape was used as a form of punishment by 38 percent of men surveyed. Fifty-nine percent had raped for "entertainment."
"Perhaps surprisingly, the least common motivation was alcohol." Fulu said.
"More than half of non-partner rape perpetrators first did so as adolescents, which affirms that young people are a crucial target population for prevention of rape," said Dr. Michele Decker from the Johns Hopkins Bloomberg School of Public Health.
"We now need to move towards a culture of preventing the perpetration of rape from ever occurring, rather than relying on prevention through responses," said Rachel Jewkes, who led the research in Papua New Guinea.
Earlier this year, the World Health Organization reported one in three women worldwide experience sexual or physical violence, calling the it a "global health problem of epidemic proportions."