They are among Australia's invisible children — seven-year-old twins Angelo and Patricia Gibia's births were never registered.

It is a common story in Queensland's remote Indigenous communities, where 20 per cent of all births are not recorded.

On Thursday Island in the Torres Strait, the twins' mother Margaret Gibia said she always intended to do the paperwork but never got around to it.

"I went to fill out the forms [when they were born] but then I lost them," Ms Gibia said.

But she is about to correct the record to ensure Angelo and Patricia have a birth certificate.

At the old hall on Thursday Island, off the tip of far north Queensland, staff from Queensland's Department of Births, Deaths and Marriages have set up plastic tables and chairs with laptops.

Some of the parents seem embarrassed to be there, leaning forward and whispering not only their children's details, but their own, to department staff — as they themselves were never registered.

Seven-year-old Patricia with her mother, Margaret Gibia. ( ABC News: Kristy Sexton-McGrath )

Queensland registrar-general David John is busy cooking sausages and onions on a barbecue nearby — the first of many that will be held in remote centres, as they try to boost Indigenous birth registration rates.

"It would appear that awareness is a big thing and the value in registering a birth," Mr John said.

"The more remote the citizen lives, the less likely they are to have the full suite of identity documents required to prove one's identity."

Earlier this year, the Queensland Ombudsman labelled previous efforts to address the problem inefficient and discriminatory.

It also raised concerns about the impact of online registration and recommended that late fees and penalties be reviewed.

Tara Vearnbombe and her children, Quinnie and Ilan Tibits-Vearncombe. ( ABC News: Kristy Sexton-McGrath )

For children like Angelo and Patricia, not having a birth certificate had not impacted on their ability to attend school — most people without a certificate had already established an identity through Medicare and Centrelink.

"The main issue they face [without a birth certificate] is trying to get a tax file number or a licence or a passport," Mr John said.

Thursday Island resident Tara Vearncombe turned up at the hall for the Births, Deaths and Marriages visit.

She said while she had both of her children's births registered at the local hospital, she was using the department visit as an opportunity to get a birth certificate for her youngest child, Ilan.

"It's not that convenient when you live remotely," Ms Vearncombe said.

Murray Island resident Dianna Passi said she found the process of registering the birth of her daughter easy.

But she said others who gave birth at home on remote islands had a harder time.

"Many people living on the islands can't speak English, they can't read or write — they can also be very shy," Ms Passi said.

Dianna Passi with her baby daughter Rosemary, from Murray Island in the Torres Strait. ( ABC News: Kristy Sexton-McGrath )

Mr John said the department would continue visiting remote Indigenous communities.

"A birth certificate formalises a person's identity and by registering a birth that information is held in perpetuity," Mr John said.

"We have 6 million records dating back to the mid 1800s — we want everyone to be counted."