When they got back at 4am after celebrating the Pumas' win, they learned the flat had been broken into and the two jerseys were stolen along with other clothes and make-up.
"The [jerseys are] something that can't be replaced and they're something that is quite sentimental too," Miss Bullock told the Herald.
Miss Bullock, 22, met Mr Leguizamon when she lived in Argentina for a year and she became close to him and the Argentina player.
She said one of the girls who lives at the flat saw two girls leaving the house on Watson St about 9pm who were acting suspiciously.
"She saw two little girls hanging out by the house next-door with a big bag ... They were lurking about and looking really weird and had odd body language," she said.
"They just took mostly girls' clothes, but the bag the jerseys were in was taken as well - I don't think they knew what they were taking, those jerseys can't be replaced."
The jerseys were those of England's number 6, Tom Croft, and Romania's number 8, Daniel Carpo.
The theft was reported to the Wellington police station, but Miss Bullock also wanted to publicise the story in case a guilty conscience led to the jerseys' return. Miss Bullock said she, Mr Leguizamon and his brother wanted to offer a reward for the jerseys' safe return.
"This is Argentina's second World Cup and it just sucks that these were taken by two little girls who don't even know the value of it."
Mr Leguizamon sent his brother a message through Facebook that night to let him know that the jerseys were gone. "Juan was absolutely gutted about it and was angry that they were gone - he just wants them back."
The jersey thefts were not a good look for New Zealand and its hospitality towards the visiting international teams, Miss Bullock said.
* If you have the stolen jerseys or know anything about their whereabouts, please contact Wellington police station on (04) 381 2000 or anonymously call Crimestoppers on 0800 555 111.