An inquest into the electrocution of a man on a prawn trawler in the Gulf of Carpentaria has been told most commercial boats in Darwin Harbour do not meet electrical standards and more people could be killed.

Key points: Darwin Harbour boats failing to meet electrical standards

Darwin Harbour boats failing to meet electrical standards Uncertain marine safety regulation could lead to more deaths, inquest hears

Uncertain marine safety regulation could lead to more deaths, inquest hears Trawler electrocution not an isolated accident

Ryan Donoghue, 20, was using an angle grinder to cut rusted shackles on the deck of Austral Fisheries' Newfish 1 when he was hit by a wave and electrocuted in November 2013.

The 240-volt power tool was plugged into a socket that did not have a safety switch, known as a residual current device (RCD).

NT Transport Department principal marine safety officer Srishailam Srinivas told the inquest his team had started boarding boats in Darwin Harbour this year to request electrical certification.

"I am very concerned," he said. "Our surveyors have been asking for the electrical certification ... rather than wait for somebody else to be killed."

Mr Srinivas told coroner Greg Cavanagh 80 per cent of boats boarded were not fitted with RCDs and needed re-wiring.

He said requests for electrical certification had been met with anger from local boat owners and some had threatened to complain about him to the NT Transport Minister.

"We're having conflict with the local owners," Mr Srinivas said. "They're not happy to spend the money."

Not a single boat audited, inquest told

The inquest heard marine safety regulation across Australia was complex and uncertain, with common areas of responsibility between local workplace safety authorities and the national regulator, the Australian Marine Safety Authority (AMSA).

The disassembled electricity outlet on the prawn trawler Newfish 1, showing a build up of foreign matter in the housing. ( Supplied )

Prior to the introduction of national commercial vessel laws in 2013, states and territories had separate marine safety and workplace safety laws.

"This resulted in legislative conflicts, unclear responsibilities, with subsequent buck passing, confusion ... leading to lower safety outcomes," Mr Srinivas said.

The inquest has been told "grandfathering" arrangements under national laws have excused many older commercial boats from compliance with new standards.

Mr Srinivas said currently a "trust and verify" model operated, where "AMSA trusts the owner to do the right thing by maintaining and operating a safe vessel".

"I am not aware of a single case of a vessel being audited to date," he said.

Mr Srinivas recommended AMSA create a clear checklist for an electrician's certificate of compliance and a system of qualified independent auditors.

"All we want is some guidance, a clear checklist that can be used."

Ryan's death 'not the first'

Marine electrical expert Ian Ritchie told the inquest that despite the regulatory confusion, commercial boats were legally required to protect sockets with RCDs.

Mr Ritchie said certificates of compliance for Newfish 1 should not have been issued because the trawler's electrical systems were not compliant.

He also said Marine Services Queensland accepted an electrical contractor's statement for the trawler from the same man who completed a statement for it prior to Mr Donoghue's electrocution.

"I think there's definitely a conflict of interest and not only that ... there were errors in the statement as well," Mr Ritchie said.

"Ryan's death was utterly tragic and it was not the first to have occurred in such circumstances," counsel assisting the coroner, Kelvin Currie, told the inquest on Monday, citing the case of a deckhand who died in similar circumstances to Mr Donoghue while using an electric grinder on a prawn trawler in Western Australia.

The inquest continues.