Mr Newall, 27, was arrested three weeks ago on his way to the Canary Islands when his yacht was intercepted by two Royal Navy vessels and escorted to Gibraltar, where he is being held in custody.
He is wanted by Jersey police to face charges in connection with the murder of his parents Nicholas and Elizabeth Newall on the island five years ago.
Chris Finch, Mr Newall's lawyer, said his client had been 'contrived' from his yacht on to the warship on the pretence of papers being examined, but he was then brought back by gunpoint. 'This is the closest to modern piracy one can imagine,' Mr Finch told the Gibraltar hearing.
He also claimed the warrant for Mr Newall's arrest 'may not have been properly issued'.
Under Gibraltar's Fugitive Offenders Act, a warrant should only be issued in Gibraltar if the individual is within the Rock's jurisdiction or on his way there, he said.
'He was not on his way to Gibraltar but to the Canary Islands,' Mr Finch said, adding: 'Are we to become the extradition box of the world?'
But John Blackburn Gittings, Gibraltar's Attorney General, said: 'Whether he intended to come here or not is irrelevant. He was lawfully arrested at sea on a British vessel.
'This man was wanted for two murders in which no bodies were found and we do not know the circumstances. Mr and Mrs Newall came to a violent end, it could have been a knife or a gun. What were the officers expected to do? Are we to say, 'Would you mind popping over for a moment? We want to arrest you for murdering your mother and father'?'
He added: 'Whether he was arrested at gunpoint or imprisoned upside down, he arrived here in one piece. He faces charges of patricide and matricide.'
Judge Felix Pizzarello said the circumstances of Mr Newall's arrest 'worried' him but he reserved judgment. He will rule on Mr Finch's submissions next week.
Mr Newall, a former Royal Green Jackets lieutenant who was making his fourth appearance before the Gibraltar court, was further remanded in custody for a week, with no application for bail.