Magistrates' Court General Civil Procedure Rules 2020

A third party who has a claim against the defendant may assert the claim in the proceeding by way of counterclaim and Rule 10.02 applies as if the claim by third party notice were a proceeding commenced by a complaint.

A third party who counterclaims may join the plaintiff as defendant to the counterclaim along with the defendant if the plaintiff and defendant could be joined properly as defendants in accordance with Rule 9.02 in a separate proceeding brought against them by the third party.