The 54-year-old is accused of killing his wife Karen at their Avondale Heights home in June 2016 and dumping her body in the bush.
He is currently facing a committal hearing to determine whether there is enough evidence for him to stand trial for murder.
“I will be making submissions that your honour should not commit on murder but manslaughter is open,” his defence lawyer David Hallowes SC told Melbourne Magistrates Court.
Arguing to drop the charges from murder to manslaughter does not mean Borce will plead guilty. 7 News reports he will maintain his innocence.