A man detained by police for eight days over an alleged terror plot to bring down an Etihad plane has cleared his name, after the "weapon" he was charged with possessing turned out to be a modified fly swat.

Khaled Merhi, 40, was charged with possessing or using a prohibited weapon without a permit after New South Wales Police found the fly swat during a counter-terror raid on his Surry Hills home in July 2017.

The spray painter's solicitor, Luke Del Monte, told the court his client had only modified the "tennis racquet-shaped" fly swat so he could use it to light his barbeque.

Mr Merhi was held for more than a week over an alleged plot to bring down the plane using a bomb hidden inside a meat grinder, but was released without being charged with terrorism offences.

At the time, police described it as a home-made taser, but on Wednesday acknowledged the device was significantly less powerful than the ones used by them.

"A NSW Police taser emits less than 300 times the voltage of this particular implement," police prosecutor Amin Assaad told the court.

"This was an improvised fly swatter."

The device was first used as a fly swatter, before being converted to a barbecue lighter. ( Supplied: NSW Police )

Court documents state that Mr Merhi told police he made the 26-centimetre-long device about four or five years ago.

"I made a little... used an old mobile phone, it was an old tennis racquet and it's for swatting the mosquitos," Mr Merhi said.

"The phone died so I used the battery out of the phone to connect to this mosquito zapper which I made so I can turn the gas stove on - you'll see it in my room."

Police said Mr Merhi told them he used an old Samsung mobile phone to wire up to the racquet "with two prongs which create a little spark for the barbeque".

The court was told that during the counter-terror raid Mr Merhi suffered a gash to the face and a back injury.

"You can see how in all of that jostling there are casualties like you with regards to the personal and physical impact that this has had on you, so I'm taking all of that into account," Magistrate Jacqueline Milledge said.

Police did not seek a penalty, conviction or costs and Magistrate Milledge did not impose them.

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Outside court the ABC asked Mr Merhi if he would now take civil action against the NSW Police for keeping him in custody for eight days but he did not answer.

In total, four men were arrested over the alleged bomb plot.

Two brothers, Khaled Khayat, 49, and Mahmoud Khayat, 32, pleaded not guilty earlier this month to planning or preparing to commit a terrorist act.

The fourth man was also arrested but released without charge.