rates on vacant land

cardina shire council has just sent me my rates notice on my vacant block of land which will be built on soon. the land has been valued at $100.000 ..not alot for a block of land. i was shocked at the rates charge $718.00. i gave them a ring and asked them if it was a error .. apparently not ,they had doubled the rating on vacant land 6 yrs ago and said they charge that much to get people to build quickly i rang a neighbouring council and asked them how much they would charge they gave me a estimate of between $300 to $400. i know cardinia is expanding and needs alot of infastrucure but that figure to me in normal circumstances would be for a land and house. . has anyone else had excessive rate charge on vacant land? has land or built in the shire of cardinia? is this excessive or not?