Subdivision and CGT

Hi, i've read a lot of forums cant seem to find the answer I'm looking for.

Our scenario is-

* We've purchased a 3 x bedroom house on a block of land approx 1800sqm
* We want to subdivide to create 2 x blocks of land @ 600sqm, keep the house and then either sell land individually or both together
* We would probably be wanting to do this within a year of purchase
* How would the CGT be applied in this scenario and would it be better to wait 12 months to reduce CGT if it does apply?

Would really appreciate anyones advice on this.