If you or your partner are permanent residents in Australia and your children are born overseas, it can take up to 18 months for them to be able to enter and live permanently in the country with you.
In that case, the process includes having to apply for a Child Visa 101 - the approval of which requires certain criteria being met.
“Only children born to Australian citizens and permanent residents in Australia acquire Australian Citizenship by birth,” explains migration lawyer Judy Hamawi.
“On the other hand, children born to Australian citizens overseas acquire Australian Citizenship by descent once the Australian parent registers their birth with the Australian embassy in the country they are born in.”

Source: Moment RF
Children born in Australia automatically acquire Australian citizenship if at least one parent is an Australian citizen or a permanent resident at the time of the child's birth, according to the (DHA) website.
Children born overseas to permanent residents
The situation radically changes if the children of one or two non-Australian permanent residents are born outside Australia. In that case the children do not automatically acquire Australian citizenship, nor are they eligible for citizenship by descent.
To enter and live in Australia, children born outside of Australia to permanent resident parents will need to apply for and be granted a permanent visa.
According to the DHA website, most of the children born outside Australia to permanent resident parents will need to apply for the Child (subclass 101) visa, which has a processing time of 12 months for 75 percent of the applications, and up to 17 months for 90 percent of the requests.
This means that if you and your partner are not Australian citizens and your children are born overseas, it can take up to a year and a half year from the moment you apply before they can enter and live with you Australia.
All those who apply for a Child (subclass 101) visa, including applicants who are the children of permanent residents, must meet the eligibility requirements and pay the associated charges for the relevant visa.

New parents watching babies in hospital nursery Source: Brand X
The basic cost for the application process starts at $2,740 AUD but that's in addition to the expense of health assessments and police certificates, plus any other certificates or necessary tests.
Ms Hamawi stressed the need for non-Australian parents to waive their right to custody of the child in order for the Australian parent to sponsor the child via the Child Visa (101).
Children born in Australia to permanent resident parents
The situation is significantly different if the children are born in Australia to permanent residents.
In that case, children born to at least one parent who holds a permanent residency in Australia acquire Australian citizenship automatically. Nevertheless, the nationality is not immediately indicated on the birth certificate - that only indicates the place of birth.
And in case non-Australian parents were to apply for a passport for their Australia-born children, the existing documents provided at birth would not be enough to obtain the travel document.
Giulia Baldini is an a Italian citizen and permanent resident in Australia. She has been living in Sydney with her Italian husband – a permanent resident as well - for the past eight years.

Source: AAP
In August 2017 the couple had their first child, a girl born in Sydney. Giulia said that obtaining an Australian passport for her daughter required an extra passage.
“Together with our Italian passports, our permanent residency documents and her birth certificate, we had to request and obtain a separate citizenship certificate for our daughter," she said.
Children born in Australia to temporary visa holders
When it comes to children born in Australia to parents on temporary visas Ms Hamawi explains that children are granted visas with conditions similar to those of their parents’ visa.
“Children born to temporary visa holders in Australia are granted temporary visas. But it is important to note that children born in Australia who hold temporary visas and live in Australia for 10 consecutive years, are eligible to apply and be granted Australian citizenship”.