The helicopter was delivering supplies to peacekeepers recently deployed to the town of Dongo in Equateur province when it was attacked at around 2 pm (1300 GMT), a spokesperson for the mission, known as MONUC, said.
"It was attacked while it was on the ground. It seems that there were five people wounded, but their lives are not in danger," Madnodje Mounoubai told Reuters.
It was the second time this week that armed men have fired on UN helicopters in Dongo, where around 20 Ghanaian peacekeepers were deployed to help quell tribal clashes that have killed more than 100 people in recent weeks.
The fighting is not related to the simmering conflict in the mineral-rich eastern borderlands, where the army – backed by thousands of peacekeepers are attempting to stamp out local, Rwandan, and Ugandan rebels.
Local Lobala and Boba tribesmen have for months feuded over fishing rights. The clashes escalated when heavily armed villagers killed at least 100 people, including at least 47 policemen, in Dongo last month. Eleven villagers were killed in two attacks last week.
At least 50 000 people have been forced to flee their homes because of the fighting.