When Sophie Ding and Ben Meng had their second child, something had to give.

Paying their mortgage and childcare, coupled with Sydney's sky-high cost of living, was taking its toll.

After their daughter Valerie's first birthday, they sent her in September to their native China to be cared for by her grandparents in Sichuan.

"I cried really bad at the airport after she left," said Ms Ding, who moved to Australia in 2005 before meeting her husband.

"At the time, I just thought I shouldn't have sent her back. I felt so bad."

Ben Ming and Sophie Ding's daughter Valerie may be far away, but she is at the forefront of their mind. ( ABC News: Selby Stewart )

They are not the only ones choosing to send a child to stay with family abroad in a bid to make ends meet.

A report from the University of Notre Dame which looked at one suburb in Western Sydney with a high Chinese migrant population found 19 children had been sent overseas temporarily to be raised by their grandparents.

It revealed children are most commonly separated from their parents between the ages of zero and five and spend an average 20 months overseas.

The youngsters who are sent overseas even have a nickname — "satellite babies".

According to the study, some migrant parents, who are less likely to be surrounded by a family support network, opt to have grandparents raise their children in their birth country while they work or study full-time.

Ms Ding said she had peace of mind knowing their young daughter is being looked after by her own parents rather than at childcare.

Ben Meng and Sophie Ding video chat with Valerie and her grandfather. ( ABC News: Selby Stewart )

Ms Ding and Mr Meng stay connected with her via Chinese social media app WeChat.

"We check WeChat every day to see if we have any photos coming from overseas of Valerie," Mr Ding said.

"Did she have a haircut? What's going on today?"

Rising living costs contribute to tough decision

Shanthi Robertson, a migration researcher at Western Sydney University, said financial difficulties were the main reason parents would choose to make their children satellite babies.

"They might not have access to government-subsided childcare on temporary visas and cost of living is getting pretty serious in cities like Melbourne and Sydney," she said.

Rising living costs continue to be a big problem in Australia with housing and childcare costs among the contributing factors.

Sydney was ranked as the 16th most expensive city to live in according to this year's Economist Intelligence Unit's Worldwide Cost of Living survey.

But there is also a cultural component to driving the satellite babies phenomenon.

"This is common in countries where three-generation care models are really common and it's really common for grandparents to play a large role in their grandchildren's lives," Dr Robertson said.

According to the study, some migrant parents opt to have their grandparents raise their children in their birth country. ( Supplied )

Dr Robertson said most parents she spoke to agreed the decision to send their children overseas was difficult.

"I think parents see it as a sacrifice that they make so they can build a better life in the long-term for their children and their families and they really feel like it's the best thing they can do for their children at that point in time," she said.

While Ms Ding's daughter is 9,000 kilometres away, she is always at the front of mind.

"Even though without her being around is very easy, I don't want to miss out on watching her growing up, like I already missed her first few steps," Ms Ding said

"She started to walk when she was in China."