A Tamil woman locked in immigration detention for the term of her pregnancy after the Australian Security Intelligence Organisation branded her a security risk, has given birth to a boy.

But the father will be prevented from seeing his son inside the detention residence, instead forced to abide by the regular visiting hours at the secure housing complex in Sydney where the mother and baby will be held. He will only be permitted in the designated visitors areas and cannot spend the night.

Tamil woman Ranjini gave birth in detention after being deemed a security risk.

The restrictions are a further blow to Ranjini, who was granted refugee protection by Australian authorities and previously was free to live in the community with her husband Ganesh before the adverse security assessment.

The two met in Australia and married last year, living in Melbourne's north-east.