Two ISIS brides were charged with slavery offences after landing in Melbourne on Thursday night - with one accused of keeping a slave in Syria that was purchased for $US10,000 ($AU13,875). 

Kawsar Abbas, 54, and Zeinab Ahmed, 31, were charged with enslavement and using a slave. Abbas was also charged with possessing a slave and engaging in slave trading.

'It will be alleged the woman [Abbas] travelled to Syria in 2014 with her husband and children, and was complicit in the purchase of a female slave for US$10,000 ($13,875) and knowingly kept the woman in the home,' the Australian Federal Police said in a statement.

The mother and daughter were taken into police custody after arriving at Melbourne Airport and are expected to face Melbourne Magistrates Court on Friday.

The alleged slave owners flew in from Syria where they had been living in the al-Roj refugee camp for seven years after leaving Australia to join their Islamic State partners.

According to the AFP, the two women were detained in the camp by Kurdish forces in March 2019.

Abbas travelled to Syria with Zeinab and her other daughter Zahra to join her husband Muhammad Ahmed.

The fourth woman who returned to Australia was not arrested. 

It has been confirmed the children of ISIS brides will enter anti-radicalisation programs and receive psychological support as they attempt to launch a new life in Australia after spending most of their lives in war zones and decrepit camps.

AFP Assistant Commissioner for Counter Terrorism,Stephen Nutt, said the investigation was active and involved 'very serious allegations'.

'Australian JCTTs [Joint Counter Terrorism Teams] methodically investigated all Australians who travelled to declared conflict areas and will ensure those who are alleged to have committed a criminal offence are put before the courts,' Assistant Commissioner Nutt said.

'JCTTs include some of the most experienced national security investigators and analysts in our country. This remains an active investigation into very serious allegations.'

Victoria Police Assistant Commissioner Martin O’Brien said the safety of all Victorians remains paramount.

'Victoria Police will continue to work closely with our law enforcement partners and other agencies to ensure there is no risk to our local community,' he said.

'We want to reassure all Victorians that anyone residing in our state who has committed serious criminal offences, including those returning from conflict areas, will be held to account.'

The ISIS brides' return to Australia had been the subject of heated political debate and intense media scrutiny.

The federal government has insisted it had no role in their repatriation and it could do little to intervene as the women were Australian citizens.

'It has always been the position of this government that we have not assisted the return of any of these people,' Labor Minister Tim Ayers told Nine’s Today show.

'[There are] very strongly held views in the government that they should not have gone in the first place.'

Nationals Leader Matt Canavan said the government should have accessed special powers to deny the women entry.

'We offered to give the government more powers that were rejected,' Canavan told ABC Radio National on Friday morning.

'I think what’s really important now is that the prime minister come out today and explain how this has helped and he should explain to Australian people how he’s keeping them safe.'

Deputy Liberal leader Jane Hume also said the government should have done more to deny passports or issue temporary protection orders.

Hume told Seven's Sunrise show about a young Yazidi woman now living in Australia who was one of the children enslaved by Islamic State families.

'The trauma this woman has gone through is unimaginable. And now people just like her captors have been invited back to Australia,' Hume told the show.

The Yazidi woman said she was interviewed by the Australian Federal Police and would be willing to give evidence during the court proceedings. 

The alleged victim said she was 11 when she was abducted by ISIS and 13 when she was taken to the home of Mohammed Ahmad who she knew as 'Abu Omar'.

'I had to stay with them for three days and if they liked my work, they were going to buy me,' the alleged victim told the ABC.

'It was very unpleasant. I was their slave and they could do whatever they wanted to me. My life was controlled by them. It felt like my existence did not matter.'  

The brides have been charged with crimes against humanity and will face court kater today.