Visiting Australia with a felony

I'm an Aussie married to an American. We live in USA. He was charged but never convicted of arson 25yrs ago, they did charge him with fraud. He got probation of 3yrs but was released after 18months. No jail time was served. We want to visit my family in Australia. Do you see any problems with that or should we contact the Australian embassy/consulate before we book flights?