Seneviratne also requested Sri Lankans to call Katmandu embassy on 0097714720623 or 00947714720213 prior to making any visits.
Nepal, which emerged from civil war in 2006, is in the final stages of preparing a new constitution that would carve the country of 28 million people into seven federal provinces.
Violent protests against a proposed new constitution intensified in Nepal's southern plains on Wednesday with demonstrators attacking police who shot dead at least four people, officers said.