The family and friends of one of four people shot dead in Darwin on Tuesday have wept as they paid tribute to someone they remembered as "an excellent man of great reputation".

Mr Sisois, 57, was the third of four men to be killed on Tuesday night during a shooting rampage.

He was killed at the Buff Club in Stuart Park shortly after 6:00pm.

Alleged gunman Benjamin Glenn Hoffmann has been charged with four counts of murder and remanded in custody.

On Thursday, about two dozen friends and family attended the Buff Club to lay flowers in Mr Sisois's memory.

He was a roofer and avid fisherman who arrived in Darwin in 1970 with his parents and six siblings, from the island of Kalymnos in Greece.

Greek-born Darwin man Michael Sisois was shot at the Buff Club in Stuart Park. ( Supplied )

"Michael was a much-loved son, brother and uncle. He loved and adored his nephews and his nieces like they were his own," said his nephew Charlie Maillis.

"Whoever knew Michael knew what a humble and harmless man he was. All he ever did was love his family and his friends.

"Our family would like to send our condolences to all the families who've been affected in this tragic and selfish event.

"Michael will never be forgotten and will forever be in our hearts until we meet again. Love you heaps, uncle."

Mr Sisois's nephew, Themeli Maillis, broke down in tears as he described his uncle as a man who greeted children of the family with an unforgettable smile.

"He took my fishing buddy away," he wept.

"He never did anything to harm a fly, he could never hurt anyone. I don't know why he deserved it."

Tributes flow for Darwin man Michael Sisois, killed during a shootings. ( ABC News: Terry McDonald )

Victim and alleged killer worked together

Family friend Jenny Katsotourhis said Mr Sisois had recently worked with his alleged killer Benjamin Hoffmann as a roofer.

"Sisois had befriended him, he had been friends with him for quite a while, [but] he hadn't been friends with him for many, many years because [Mr Hoffmann] was in prison," she told the ABC.

"Sisois… was an excellent man of great reputation. He would've given anyone the shirt off his back, and that's contributed to this."

She said the men had worked together since January, when Mr Hoffmann was bailed.

The victim's brother, Vince Sisois, said his family might "have to have guns to go out and protect ourselves". ( ABC News: Terry McDonald )

Second time gun tragedy strikes family

This is not the first time the family has lost a loved one to gun violence.

In 1987, Mr Sisois's sister, Niki Voukelatous, was shot dead in Blackburn South in Victoria.

The second tragedy had hit the family hard, said Mr Sisois's brother, Vince.

"We lost second member now in this family in the same manner," he said, visibly angry.

"It has to be changed, something, otherwise we will have to have guns to go out and protect ourselves, cowboy-style like the old days.

"Never happen to Darwin, I've been here half a century… never done anything bad.

"We're good citizens, we're hard workers… two people from my family [killed who] come here for a normal life, not to leave our bodies here before [our time]."

Mourners lay flowers for Darwin shooting victim Michael Sisois at the Buffalo Club. ( ABC News: Rosa Ellen )

New Zealander shot outside his home

Northern Territory Police Commissioner Reece Kershaw told reporters on Thursday that it was "highly likely" Rob Courtney, 52, also knew his attacker.

Mr Courtney was the last to be killed, shot outside his home in Jolly Street.

The Mindil Beach Casino said Mr Courtney was a valued member of its security team.

A spokesperson for the New Zealand Ministry of Foreign Affairs and Trade said the office was aware of the death of one of its citizens in Darwin.

"New Zealand extends its sympathy to the people of Darwin and Australia after this shooting," the statement said.

"Authorities have been in contact with the family of a New Zealander affected by the incident."

When asked by a reporter whether the rampage was brought to an end because Mr Courtney scuffled with the alleged killer with a knife before succumbing to his gunshot wounds, NT Police Commissioner Reece Kershaw said: "Yes, that is a possibility."

Police are yet to identify the fourth victim of Tuesday's shooting, a 76-year-old man killed at Gardens Hill Road.