Any members displaying such symbols will face fast-track expulsion from the party, Beatriz Jurado, the leader of the PP's youth wing Nuevas Generaciones (NNGG) said.
The move comes after recent instances of NNGG members displaying the nationalist Spanish flag used during the rule of Spanish dictator Francisco Franco.
In other cases, Nazi salutes were performed.
The PP is now taking legal action against six NNGG members, El País reported on Wednesday.
Speaking about the decision, NNGG president Jurado expressed condemned any actions involving fascist symbols while the PP's Deputy-Secretary for Studies and Programmes, Esteban González Pons, said "those who commit this (type of) stupidity don't deserve to be in the PP."
"I find it disgraceful that someone would brag about being a Nazi or make fun (of people) with these symbols. I don't think they know what they are doing," he said.
PP parliamentary spokesperson Rafael Hernando then muddied the waters by declaring that any member of Spain's socialist opposition PSOE party displaying Spain's Republican flag should also be expelled.