Michael Ibrahim, who was with older brother Fadi Ibrahim, had been in the United Arab Emirates for just over a week - the Middle Eastern monarchy long regarded as a safe haven for criminals to do business and hide out.

But Australian police had been making plans of their own for more than two years and after dinner Dubai police's anti-narcotics unit swooped, arresting all five in one of the largest crackdowns on organised crime in Australia.

Michael Ibrahim is understood to allegedly be the common link between two long-running syndicates helmed by warring, violent factions of Sydney's underworld who had allegedly been flooding Sydney with ecstasy, cocaine and ice for years.

The Dubai arrests, which also included Sydney underworld figures Steven Fawaz Elmir, Hakan Arif and Mustapha Dib, triggered raids by more than 500 police officers at 30 properties across Sydney. Those properties included the Dover Heights home of John Ibrahim, with the nightclub tsar holed up inside as police searched the gutters and smashed their way into a safe that Ibrahim had forgotten the code to.

Police arrested 10 people in Sydney, including his girlfriend Sarah Budge, who was allegedly found with a loaded Glock pistol. His son Daniel, his cousin Sleiman Tajjour and his friend and real estate agent Ryan Watsford, 37, of Rose Bay, were also charged in relation to drug importation and dealing with more than $1 million in proceeds of crime.

Three Dutch nationals were arrested in the Netherlands, allegedly involved in a shipment of ice found in a shipping container and intercepted on its way to Australia in recent days.

The five men arrested in Dubai are believed to have been key players behind the two syndicates that spanned three continents.

"The best way to do that is to attack the top of the tree and we'll bring the tree down," AFP Assistant Commissioner Neil Gaughan said of the smashing of the syndicate.

"We'll take the fight offshore and we're going to bring the men to justice."

The investigation, known as Operation Veyda, resulted in the seizure of 1.8 tonnes of MDMA, 136 kilograms of cocaine, 15 kilograms of ice and $5.5 million in cash.

All of those drugs were destined for the Sydney market.

"This is only the beginning," Mr Gaughan said. "We are aware that there are other Australians, organised criminals, who operate in other parts of the world. We will one day come knocking on your door."

It is understood one syndicate involved Elmir and his associates Arif and Dib.

The other is believed to have involved the notorious Ahmad family, and Ahmad "Rock" Ahmad, 39, was among those arrested in Sydney on Tuesday.

He covered his face with his hands and a hooded jumper when he appeared via audiovisual link at Central Local Court on Tuesday, where he was refused bail.

The Elmirs and the Ahmads have been involved in a bloody feud for more than a year that has resulted in four deaths, including that of Rock Ahmad's brother, standover man Walid "Wally" Ahmad, at Bankstown Centro in April 2016.

Michael Ibrahim and Fadi Ibrahim were among the mourners at Wally Ahmad's funeral.

Michael Ibrahim is expected to be charged with multiple offences relating to conspiracy to import a commercial quantity of drugs and money laundering. Fadi and Daniel will be charged with dealing with the proceeds of crime.

Michael Ibrahim was released from jail in 2014 after serving six years for the manslaughter of Robin Nassour, brother of Fat Pizza comedian George Nassour. Since his release, Michael Ibrahim has made numerous trips to Dubai, even posting photos of himself sitting in business class on a flight.

Elmir fled Sydney after his brother-in-law was killed in a shootout with the Ahmad family at Condell Park and is believed to have been living in Dubai. He is alleged to have been working with Arif, a former airconditioning serviceman, who has long been the right-hand man to wanted drug smuggler Hakan Ayik and Dib.

Known as "Fairy", Dib was released from jail in 2016 after his conviction for killing schoolboy Edward Lee was quashed by the High Court. He was part of the infamous Telopea St gang that wrought havoc through the south-west suburbs in the late '90s. Arrested in Sydney was their associate and Lone Wolf bikie Hassan "Faks" Fakhreddine.

Police will apply to extradite the Ibrahim brothers as well as Elmir, Arif and Dib from Dubai.