Well, actually, 'aunty' and 'auntie' are just informal versions of the word 'aunt', and so both are okay to use.

What do you mean by aunties?

Noun. 1. auntie - the sister of your father or mother; the wife of your uncle. aunt, aunty. grandaunt, great-aunt - an aunt of your father or mother.

Is there a word aunties?

noun Informal. the plural of auntie or aunty.