I can state unequivocally that my passport was required, as well as my visa, on entering Paraguay at the Clorinda border crossing as recently as two weeks ago.
We drove to Paraguay from BA. I offered my DNI (permanent resident, foreign citizen) and the exiting migraciones officer for Argentina had no problems with my leaving the country just on my DNI. On the Paraguayan side I did the same thing, handed the officer my DNI and they asked for my passport and paged through until they found my visa to verify I had a visa for Paraguay.
When I returned to Argentina, I was again asked for my passport by the Paraguayan official and I did not have to show my passport to the Argentine.
We drove to Paraguay from BA. I offered my DNI (permanent resident, foreign citizen) and the exiting migraciones officer for Argentina had no problems with my leaving the country just on my DNI. On the Paraguayan side I did the same thing, handed the officer my DNI and they asked for my passport and paged through until they found my visa to verify I had a visa for Paraguay.
When I returned to Argentina, I was again asked for my passport by the Paraguayan official and I did not have to show my passport to the Argentine.
