*DISCLAIMER - PLEASE NOTE THAT THIS IS NOT A SUBSTITUTE FOR PROPER LEGAL ADVICE PERTAINING TO YOUR OWN SITUATION *

Dee;

It depends on how the child support agreement was made.

If the amount is calculated by the Child Support Agency, then a defacto does not change the amount payable, unless the defacto is pregnant.

A child of the defacto couple (ie the payer and the new defacto) will reduce the amount payable according to the Child Support Assessment Act (basically the disregarded income amount will increase by about $2500 approximately).

If the new defacto becomes pregnant, then the payer can apply for a Change of Assessment (see the CSA for paperwork); as the payer has a legal duty to support the new defacto for two months prior to the birth and three months post the birth. Basically the new disregarded income amount will be 220% of the partnered pension, plus the extra amount for a new child.

If the amount payable is set by a Child Support Agreement then you will need to have the Agreement set aside if you wish the amount to be changed. Please obtain proper legal advice as to whether or not you have grounds for doing so.

If you need to speak with a lawyer, Victoria Legal Aid has a Ringwood office (I note you are in Blackburn South).