Troops have been sweeping northern Rakhine state for more than a week, hunting an estimated 400 fighters who officials believe are members of the mostly stateless Rohingya Muslim community acting with the support of Islamists abroad.
The Myanmar military has declared the area an "operation zone" and has tightly controlled the flow of information since insurgents seized dozens of weapons in raids on border posts on Oct. 9 in which nine police officers were killed.
UN agencies "don't have access to the affected areas to assess humanitarian needs", Pierre Peron, spokesman for the UN's Office for the Coordination of Humanitarian Affairs, said by email.
Health clinics and nutrition programs in northern Rakhine have been hampered by movement restrictions imposed after the attacks, he said.
"We hope that the situation will improve as soon as possible so that humanitarian organizations can restart vital programs to assist all communities in Rakhine state," Peron said.