The alleged mastermind behind a scheme targeting 70 disabled Australians and their carers "boasted" about the millions of dollars made in fraudulent payments from the National Disability Insurance Scheme, a Sydney court has heard.

Key points: Police seized three luxury cars, including a Porsche Cayenne, as part of raids in May

Police seized three luxury cars, including a Porsche Cayenne, as part of raids in May There are more than 100 potential victims, the AFP has said

There are more than 100 potential victims, the AFP has said Three men and two women are accused of setting up three NDIS providers to claim subsidies

Alaedine Rifai, 40, was dressed in prison greens and shook his head when Magistrate Margaret Quinn rejected his bail application, as well one made by his girlfriend and co-accused, Amal Hilmi, 35, at Central Local Court on Tuesday afternoon.

When her younger brother, Mostafa Hilmi, 30, was ordered to remain behind bars, his girlfriend and co-accused, Michelle Ross, 27, burst into tears and stormed out of the hearing before ignoring reporters outside the court.

Alhassane Hilmi, 27, who also remains behind bars, then withdrew his bail application.

Alaedine Rifai is the alleged mastermind behind an NDIS scam. ( Supplied )

The prosecutor referred to a series of WhatsApp messages between Mr Rifai and Ms Hilmi, in which both of them allegedly boasted about "hitting the $1 million mark" and that he said, "Let's keep going!".

The court heard how Ms Hilmi was still breastfeeding the couple's seven-month-old son before both were arrested while police raided homes at Lurnea and Liverpool, and a factory at Moorebank two weeks ago.

The child remains in the care of Ms Hilmi's mother, but her defence lawyer said the 64-year-old has "health issues", arguing it would be best if Ms Hilmi was granted bail to allow her to care for both of her loved ones.

But Magistrate Quinn ruled the prosecution had presented "a very strong case" and made reference to the text messages that allegedly "celebrated the large amounts of money" made off "vulnerable Australians".

"Figures in front of me show nearly $3 million," she said.

There are numerous companies set up to obtain money from the NDIS — some of it may be legitimate, but it appears some of it certainly may not."

The three men and two women are accused of setting up three NDIS providers in western Sydney to claim government subsidies to pay for luxury items, such as jewellery, cars and a property in Indonesia.

Universal Group Australia claimed to offer home modification services through the NDIS, while Reliance Disability Services and United Mission were listed as providing transport, nursing and cleaning assistance.

Police say up to 70 disabled Australians and their carers were targeted, while investigators have identified another 100 potential victims.

The alleged syndicate is due to face Central Local Court again on August 28.