I'm not sure about verbally lying to customs officers, but in my country (Australia) I know that lying on your customs declaration is an offence (making a false

I'm not sure about verbally lying to customs officers, but in my country (Australia) I know that lying on your customs declaration is an offence (making a false statement on an official document or something like that). The flight attendants have to read out a little script including that after they hand out the declaration/entry cards. I expect NZ is similar.