While Torres left undetected, she was later spoken to by police and admitted to stealing lingerie from the store.
She took police to their vehicle, where more lingerie was uncovered.
The total value of stolen items was $2353, with reparation sought for damaged items of lingerie which had tags removed.
Duty lawyer Jim Large said the trio were sorry, and had no excuses.
They were "not proud" to appear in court and could pay a fine and reparation immediately.
The trio were convicted, fined $450, and ordered to pay $500 reparation.
Immigration New Zealand fraud and compliance manager Peter Elms said foreign nationals convicted of criminal offending in New Zealand could be liable for deportation.
"Immigration New Zealand has today served the three Spanish nationals with deportation liability notices."
The women had 28 days to appeal or leave the country of their own volition, otherwise they would be deported, he said.