Ahmed Elomar, 36, has denied three charges relating to the slingshot and metal bearings found during a police search of his Sydney home in 2018.

By allegedly possessing a prohibited weapon, he is said to have breached a weapons prohibition order, and an extended supervision order imposed on him in August 2018.

At the start of his judge-alone trial in the NSW District Court on Tuesday, Acting Judge Rodney Madgwick threw out a fourth charge alleging he untruthfully answered a question from his enforcement officer on November 1, 2018 regarding his reasons for visiting a Warwick Farm petrol station.

His barrister Bret Walker SC successfully argued the charge, under NSW anti-terror legislation, specifically alleged he had lied to assigned community corrections officer Amanda Carden.

But this was not the enforcement officer to whom Elomar spoke and allegedly lied to on November 1.

Prosecutor Craig Everson had argued that an enforcement officer could constitute anyone to whom Ms Carden granted agency to speak with Elomar.

In his final submissions on the slingshot-related charges, Mr Walker argued his client was not in "possession" of the slingshot, noting he told police he believed the item belonged to a teenage relative.

His DNA was not found on the item and Elomar told police he was surprised he was charged given it was a kid's toy.

Mr Everson said the slingshot could be deemed to be dangerous to people and property.

Because of the brace attached to it, it was in the nature of a "hunting sling" and was capable of propelling items such as golf balls or bent nine-inch nails.

But Mr Walker referred to evidence given during the trial of tests in which metal pellets were fired and they did not penetrate ballistic gelatin, designed to replicate human tissue.

"In order to be a hunting sling, you must be able to wound in order to hunt," he said.

Acting Judge Madgwick is expected to deliver his verdicts on Wednesday.

Australian Associated Press