The government has flagged its intention to extend the use of control orders to children as young as 14.

The effect of a control order may range from house arrest without access to electronic communications, to a restriction on the people you can associate with. The order can remain in effect for up to 12 months.

A Malaysian man was arrested at Sydney airport over a 20-year-old Perth sex crime.

It can be obtained in a secret hearing about which the subject knows nothing at all, until they are arrested and served with the order. And even then they are not to be told what the evidence was that was used against them.

So if someone made a mistake, the subject of the order won't know and they can't find out because they are not allowed to see the evidence that was used against them.