The Oxfam report finds that if Australia lifted its humanitarian intake from 18,750 to 44,000 by 2020/23 the country's overall Gross Domestic Product would increase.

The charity's report finds the intake would add 35,000 full time equivalent jobs to the Australian economy every year, on average over 50 years.

The report's comprehensive modelling by Deloitte Access Economics shows that an increase in intake would also boost demand for Australian goods and services by $18.2 billion.

"The primary purpose of Australia's Refugee and Humanitarian intake is to provide refuge and support to people who have been forced to flee their home country in order to escape war, persecution, or a natural disaster," Oxfam Australia Chief Executive Lyn Morgain said.

The report also backs a push to make it easier for refugees and humanitarian migrants to reunite with their families.

Monash University research, commissioned by Oxfam, has found refugees and migrants who reunite with their families are more likely to resettle successfully. The research hows the affects of separation on refugees and migrants can be devastating.

Refugees who had been reunited with their families had a lower probability of mental illness and post-traumatic stress disorder (PTSD), and were more likely to be engaged in study or job training, the research found.

"I've seen just how stressful and hard it is for refugees settled in Australia to try and build a new life here, when family members they love dearly - parents, sisters and brothers, aunts, uncles or cousins - are missing, living in danger in the war-torn countries they've fled or struggling to survive in a refugee camp on the other side of the world," Ms Morgain said.

South Sudanese refugee Lucy, who migrated to Australia in 1991, was separated from her three-year old daughter due to the country's civil war in 1988.

"My heart was broken. I didn't know what to do. I just felt empty," Lucy said.

She was reunited with her daughter in Australia in 1994, but still recalls the trauma she felt being separated from her. Lucy's daughter had to grow up in a refugee camp, which meant Lucy felt like a stranger to her.

"It took us a lot of time to heal, to understand each other."

Ms Morgain said Australia had a complex refugee and humanitarian system that made many families wait for years to be reunited, and some never saw their mothers, fathers, siblings or children again.

"No family should be forced to live apart. Unified families, who love and care for one another, are the glue that binds our communities together," Ms Morgain said.

Oxfam is calling on the Australian government to take action, recommending 10,000 refugee places annually, specifically designed to make it easier for humanitarian migrants to be reunited with their family.

Australian Associated Press