The leaders, who are in New Delhi, India on invitation of Indian Prime Minister Narendra Modi, briefed the lawmaker that obstruction of essentials is caused by protest by them at border entry points.
On Monday, UDMF leaders met leader of Janata Dal (United) and lawmaker Pawan Verma.
Verma is the lawmaker who had registered an attention motion at the parliament demanding discussions over Nepal.
The leaders told Verma that the new constitution has discriminated the Madhesi community on the basis of skin color.