Melbourne-based South Sudanese woman Rosa Riak and her son Kuol Deng established home-based Hello Children Family Daycare business in 2014.

They submitted claims for carers when they were on leave and for children who they weren’t actually caring for.

Once the pair were sprung, investigators discovered the daycare scam had netted $6.2 million over a four-month period in 2015.

View photos Rosa Riak (pictured) and her son Kuol Deng will serve four years’ jail after their home-based Hello Children Family Daycare business scammed taxpayers out of more than $6 million. Source: 7 News More

At one point the scam was raking in about $880,000 a fortnight.

The mother and son kept almost $1 million, while the rest went to other carers who were in on the scam.

Once the auditors came in, Riak and Deng shut the business down and bought another.

At one stage, Deng asked his mother where he could stash $80,000 in cash.

He was later intercepted in a phone call saying: “We are too smart for them. That’s one thing I understand”.

View photos Kuol Deng and his mother Rosa Riak raked in about $880,000 a fortnight at one stage. Source: 7 News More

Family members said they felt deep shame over what happened.

In sentencing, Justice Michael McInernery said: “To have many people from that country engaged in an attack on the revenue” of Australia “is most disappointing”.

He added that millions of dollars were spent “to allay the plight” of South Sudanese refugees.

The mother and son will spend four years behind bars, while Deng’s sister, Archay, walked free on an 18-month good behaviour bond.