UNICEF's Pacfic sanitation specialist says the safety of girls and women is often overlooked when new toilet facilities are built.
The comment accompanies World Toilet Day, which has long been observed on November 19 but was made an official United Nations Day this year.
Marc Overmars says open defecation is still common in some Pacific Island countries but his organisation's community-led approach is changing that.
He says other sanitation programmes have tended to neglect what is important for girls and women.
"But once actually toilets are in place then it's important to really have sex-segregated in place in schools for instance so that girls are not actually being harrassed etc and don't feel ashamed to go actually to toilets. It's been known that indeed girls have been staying away from schools because they don't have facilities if they're menstruating etc."
Marc Overmars says toilets must also be in a safe location.