Legal Question in Family Law in Australia

If the custody agreement is a court order or registered parenting plan it must be complied with until such time as there is a court order or an agreement to change it. If not then you can apply to court for orders that the children live with you. Given their ages there is a good chance a court would order they live with you if that is their choice. However court proceedings are probably not necessary. One alternative is to have mediation involving the children so they can express their wishes. The other is that the children just leave their mother's residence and come and live with you. If their mother doesn't like it she would have to bring an application to court to have them returned to her care but she is unlikely to succeed if the children genuinely want to live with you.