The student was arrested by police at her Guildford home in western Sydney on Tuesday morning and charged with collecting money to send to a terrorist organisation.

During her bail application at Parramatta Children's Court on Wednesday, prosecutor Imad Abdul-Karim said police opposed it due to the serious nature of the allegations and the strong nature of the prosecution case.

Mr Abdul-Karim read out text conversations which he said was evidence the girl knowingly collected the money to send to her cousin, an alleged ISIS fighter.

In one text message on 21 March, prosecutors alleged the girl told a man named 'Abdul' that she knew the money would end up going to the terrorist organisation.

'Yes, I just do what (he) tells me to do,' the court heard she said.

Her plan was to transfer the $5,000 through Western Union, the prosecutor said, however she would need an adult's help as she was under-age.

The court heard the schoolgirl collected the money on 21 March and was arrested the next day.

Her defence lawyer told the court investigators found the $5,000 in her home in an envelope wrapped in elastic bands.

Other text messages between the girl's cousin and her co-accused, Milad Atai, 20, were also read out by prosecutors.

In one, the ISIS militant told Atai: 'There are a lot of rewards from aiding the mujahideen', Daily Mail reported.

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