Riitta-Leena Paunio, Finland's parliamentary ombudsman, said in a statement Monday that the Finnish Red Cross blood transfusion service's policy that sex between men was a permanent impediment to donating blood could not be considered unlawful.
The statement added that Ms Paunio's had based her decision on expert opinions.
"These statements contain appropriately reasoned epidemiological information to the effect that sex between men clearly increases the risk of contracting serious blood-transmitted diseases, such as HIV and hepatitis B and C, and thereby increases the safety risk in blood transfusion," it said.
"The ombudsman emphasises that the ban is not due to sexual orientation, which enjoys constitutional protection against discrimination, but rather to sexual behaviour."
The ombudsman underlined that in addition to gay men, the Finnish Red Cross did not accept blood from anyone over 65 years of age or people who had been to Britain during the bovine spongiform encephalopathy outbreak.