Australian Aukuso Junior Paulo, 34, and New Zealander Kigi Kamuta, 39, were two of three men arrested while travelling with two semi-automatic weapons and A$650,000 (NZ$712,000) in cash, during a planned police operation in the eastern suburbs park.
A third man, Royce Royal Hura, 27, was also arrested at the scene. Both Hura and Paulo were former players of the Parramatta Eels rugby league club in the NRL.
Following their arrest, all three men were charged with possessing an unauthorised pistol, possessing ammunition without holding a licence, knowingly dealing with proceeds of crime and participating in a criminal group.
However, on Monday, strike force investigators laid further charges against Paulo and Kamuta for the supply of 900 kilograms of cocaine.
The "far more serious charge" was apparent news to the lawyer for Paulo, Nick Hanna, who had intended on applying for bail on behalf of the 34-year-old at Central Local Court in Sydney on Tuesday.
"On arriving in court, I was informed first by a journalist and then by the prosecution that a new charge had been laid against Mr Paulo," Hanna told the court, later adding that "not even the DPP were given notice of the charge until Tuesday morning".
"It is bewildering that this charge was not filed and served on the defence yesterday ... my staff and I worked very late preparing the release application."
Expressing his frustration, Hanna said he was "not in a position to apply for release" and withdrew the application.
Bail was formally refused and Paulo will spend Christmas behind bars, to reappear via audio-visual link on February 20 next year.
As Hura was not charged in relation to the supply of the 900kg of cocaine, his legal representation continued with an application for bail on Tuesday, on grounds that the Crown's submission was "not a strong case".
His lawyer Arjun Chhabra argued that Hura was merely the driver of one of the two vehicles stopped in Centennial Park and that he did not know the contents of the backpack in the vehicle; which contained two semi-automatic firearms and ammunition and lay at the feet of the co-defendant in the passenger seat.
The A$650,000 (NZ$712,000) in cash and a number of encrypted Blackberry devices were located in the second vehicle.
Chhabra told the court of Hura's extensive family support network, many of whom were in court on Tuesday, and who would put up their own homes as surety if he were released.
However, Magistrate John Andrews ultimately found the prosecution had presented a "much stronger case".
He pointed to detailed police surveillance that indicated conversations and evidence between all three men, including Hura, in relation to the "laundering of money and the possession of firearms in Centennial Park".
Bail was formally refused, with Hura to also appear in court via audio-visual link on February 20.
Last week's dramatic arrests, in which non-lethal projectiles were deployed by police in front of a park cafe, were the result of Strike Force Mangowa, a joint State Crime Command and Australian Crime Intelligence Commission investigation into the activities of an organised criminal group in Sydney.
On Tuesday Detective Chief Superintendent Tony Cooke, head of the Organised Crime Squad, said the latest charges would "send a signal to all criminals that they can expect the full scope of the law".
"We'll use every law at our disposal to prosecute those criminals and disrupt their operations," he said.
Chief Superintendent Cooke said he could not speak about the operation in detail, but added that more arrests and charges were anticipated.
Photo by: COLLIN FLYNN/ FAIRFAX MEDIA. Caption: One of the men arrested at Sydney's Centennial Park.