re entry to australia with convictions

i was living in AUS 10 years and got convicted for robbery. it was an 18month suspended sentence(didnt spend a day inside) an no trouble after that. Ive just moved back to nz in april and wanna go back to aus for 6 months to a year or so. I have emailed asking about this and they say fill out character check etc. they said if i just show up to airport without visa and character check they will make decision at border. Does anyone know what my chances would be?If i tick no on the conviction question are they likely to bother checking me out etc?

Would i be better off just saying im on quick holiday and just stay there?