Kawasaki Heavy Industries is being sued over a workplace death in the Northern Territory. 

The widow of a man who died at Darwin's Inpex gas plant is suing Kawasaki Heavy Industries, alleging her husband would have lived if safety protocols were followed.

Terry Delaney's husband Carl died while working alone inside a large tank late in 2017. Reports say he fell into an insulation material called perlite and suffocated.

Kawasaki Heavy Industries oversaw construction of the tanks, and according to Ms Delany, the company breached a duty of care owed to her husband. JKC Australia, which was contracted to build the Bladin Point gas plant, also breached its duty of care, according to court documents.

“We say that Carl was owed a duty of care, that there was an obligation on those in charge of the site to establish, maintain and inform a safe system of work,” Darwin-based lawyer Amy Williams said.

“We say those systems that were supposed to keep Carl safe failed him.

“When companies are making really large amounts of profit on the back of our Northern Territory workers, we say that it's incumbent on those companies to make sure that a high standard of safety is in place, to make sure that there is no room for error, and to make sure that men like Carl can go home to their families each night.”

Ms Delaney is seeking compensation on behalf of Mr Delaney's three children, including for Mr Delaney's weekly income of about $2,400 for the remainder of his working years.

A coronial inquiry into the incident found that safety guidelines were regularly ignored at the site at the time of his fall.

The Northern Territory's work safety watchdog, NT WorkSafe, had filed charges against Kawasaki Heavy Industries and subcontractor Whittens Group, Mr Delaney's employer. 

However, the case against Kawasaki Heavy Industries was dismissed, while court action against Whittens Group is ongoing.