A Rise Up Australia candidate in the state election who failed to stop a local council from promoting same-sex relationships plans to take her case to the Equal Opportunity Commission, claiming she has been discriminated against.

Casey councillor Rosalie Crestani put forward her motion at a council meeting last Tuesday, but it failed to gain traction and a counter motion re-asserting the council's existing stance was passed two days later.

Councillor Rosalie Crestani with Lord Christopher Monckton. Credit:Craig Butt

In an email sent out to council staff on Monday morning, Cr Crestani wrote that the counter motion was "against the law and I shall be referring the council's discrimination against heterosexuals in general and against me in particular to the Equal Opportunity Commission".

She had been calling for the council to remove any mention of same-sex relationships from its advertising material after seeing a sign that read "You don't have to tell us if you're gay, lesbian, bi, trans or intersex - but you can" in the council building, on the grounds it failed to mention heterosexual relationships.