A Sydney mother has argued 'Islamic law' was the reason why she and her new husband were unable to look after her children.

Her refusal to look after her children forced two of them into foster care and another child, a 17-year-old boy, was allowed to live with his father who had a history of violence.

The mother, who was born in Lebanon, told the Family Court Islamic law, which is also known as Sharia law, meant her children could not live with her as her husband was not obligated to look after them.

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A Sydney mother has successfully argued 'Islamic law' was the reason why she and her new husband was unable to look after her children. Pictured is a stock image

The case heard in the NSW Family Court involved a nine-year-old and a 14-year-old whose mother married again after divorcing from their father.

'The mother has completely abrogated her responsibilities as a parent in refusing to have the children live with her and proffering as an excuse that her new husband should not be required to care for another man's children as it's contrary to Islamic law,' the judge said.

But Islamic law expert Dr Hossein Esmaeili told The Australian the mother's argument was not based on any legal basis he had heard of.

In a previous research paper, Dr Esmaeili had noted 'an increasing number of cases in Australian courts where... Muslims apply Shariah principles in their personal relationships as part of their religious observance'.

As well as following traditional Western laws, Dr Esmaeili said Muslims living in Australia also integrate parts of Sharia law into their legal agreements.

'While many Muslims in Australia do not support the introduction of Shariah law in Australia (or elsewhere), many Australian Muslims follow certain Shariah legal principles as part of their religious observances,' he wrote in a research paper.

This move forced her two children to go into foster care and her third child, a 17-year-old boy, was allowed to live his father who has a history of violence. Above is a stock image

'These include matters which ordinarily are legal issues in Australia, such as inheritance law, wills, paying special [religious] taxes (zakat), marriage and divorce, and matters relating to personal property, banking and finance.'

Dr Esmaeili also said the introduction of some elements of Sharia law into the Australian legal system could help the integration of Muslims into society.

'Recognising certain personal Muslim laws such as those dealing with marriage, divorce, wills and inheritance, banking and business, may help Muslims to access Australia's justice system more effectively and realise that the Australian legal system can accommodate certain Shariah practices by Muslims,' he argued.