The central and state governments are required to enact legislations in this regard to curb proselytisation, a resolution adopted at the conclave, said.
The resolution called upon all parties to rise above political considerations to help frame anti-conversion laws for "preserving the country's unity, integrity and security."
It further demanded that the flow of foreign money into the country in the name of social service through Christian organisations should be stopped.
It alleged that these funds were being utilised by such organisations for "converting people to Christianity" and "funding terrorist activities."
The dharma samsad would conduct a nationwide "awareness campaign" against the international conspiracy to divide the country and finish Hinduism," it said.
"If the demand is not fulfilled, the VHP would launch an agitation throughout the country," the resolution warned.
The resolution further demanded immediate deportation of about 3,000 foreign missionaries in India who had come on tourist and business visas.