File photo of United Nations Secretary-General Ban Ki-moon.
UN Secretary General Ban Ki-moon underlined his concern over the blocking of essential supplies on the Nepal-India border and the adverse impact on the humanitarian operations post the devastating earthquake in April, his spokesman said in a statement.
"Ban is alarmed by reports of the obstruction, and destruction of life-saving medical supplies and the continued impact on humanitarian operations," Xinhua quoted the report as saying on Friday.
He called on all sides to lift restrictions without further delay and underlined Nepal's right of free transit, it said.
Stressing "the importance of dialogue and non-violence, as well as respect for peaceful protest and the freedom of assembly," Ban urged all sides to resolve their differences in a peaceful and flexible manner.
He reiterated the support of the United Nations to Nepal's efforts to build a democratic, inclusive, peaceful and prosperous future, it said.
The UN Children's Fund (UNICEF) has also cautioned that the blockade of Nepal's border posts with India "threatens the future of the country itself".
The crisis in Nepal centres opposition to Nepal's new constitution, signed on September 20.
Members of the ethnic Madhesi political parties claimed that the constitution failed to guarantee them fair representation in parliament and public office.
Since September, the protesters have blocked border posts with India, leading to acute shortages of petrol, cooking gas and other essential supplies.