The Raxaul-Birgunj border in Bihar and other bordering areas were sealed after 4:30pm yesterday, according to police.
Security has been tightened in the areas fearing possible cross-border criminal activities ahead of and during the polls, officials here said.
The borders will remain close for three days effective from yesterday evening, the police said.
Barring vehicles on emergency duties, no traffic will be allowed between the two countries during the period.
Movement along various border checkpoints in Kapilvastu, Rupandehi and Nawalparasi districts will remain suspended.
The border areas at Krishnanagar, Maryadpur, Chaakarchauda of Kapilvastu; Belahiya, Meudihawa of Rupandehi and Maheshpur of Nawalparasi, were also closed.
The move follows meetings between officials from Nepal and India before the Parliamentary elections started on April 7 to discuss issues relating to border security.