There is an urgent need for more Aboriginal foster carers in New South Wales with numbers of Indigenous kids placed with First Nations families set to decrease, the peak body for Aboriginal children in the state says.

More than 6,000 Aboriginal and Torres Strait Islander children are in out-of-home care in New South Wales.

"We're only able to place about one in every five of those children with an Aboriginal foster carer which is just because we don't have enough Aboriginal foster carers," Alyssa Robinson from the Aboriginal Child, Family and Community Care State Secretariat said.

"Right across Australia, the trend is that the numbers keep increasing of Aboriginal kids removed from their families, this is something we're advocating against.

"We urgently need Aboriginal people to put their hand up and open their doors to children who really need support."

Joanne Mara wants more Indigenous people to open the door to foster children, like she has. ( Supplied: ABsec )

Aboriginal woman Joanne Mara lives in Western Sydney and has looked after 40 Indigenous foster children over the past two decades.

"A lot of the Aboriginal children who come into care have only been with Aboriginal families … they look the same as me, they talk just the same as me," she said.

"But more than that it's important that they're with Aboriginal carers so they don't lose their way, they don't lose their story.

"We make a point of finding out where the kids who come to us have come from: What is their mob? What is their country?"

There is expert evidence which says it is more beneficial for the child to be placed with an Aboriginal carer, Ms Robinson said.

"It's been shown that Aboriginal kids are stronger in their identity and more secure in their wellbeing when they have strong connections to culture, it really informs who they are and community keeps them safe," she said.

"We really want Aboriginal children to ideally be with their families or to be with Aboriginal carers because they know how important family is and our culture, they know it's important to stay connected to country and to be part of a community."

Ms Mara urged other Aboriginal people to become carers.

"It's not unusual for Aboriginal people to have family around all the time and this is very much the same, it's like being the aunty," she said.

"You can step up, you can do this, open your home and ask yourself can I give these kids somewhere to sleep for a couple of nights, can I keep them safe?"