There are several option for automatic bet placement depending on where you want to bet, i wish there was an all in one program but at this time there is not.

As mentioned there is Dynamic Odds this is not automatic but i understand they have an excel version that will let you auto bet to the NSW and VIC tabs, i did see prices of $50 a month but not sure if this includes the full service

You could contact NSW or VIC tab and ask them about the Betstream program this program monitors a folder on your pc and when a bet is dropped in to it in the correct format the bet is placed, this can be done with excel.

Unitab also have a software program that lets you drop bets just like the NSW and VIC version you would need to contact them about this also.

Another options is do a search for "The Odds Broker" not automated but lets you bet with a few bookies and all 3 tabs for free.