A Senate inquiry is due to report today on the circumstances surrounding forced adoptions in Australia.

The inquiry has taken a year to gather accounts and evidence from hundreds of relinquishing mothers across the country.

Prior to today's anticipated senate report, ABC1's Four Corners spoke to a former social worker who recounted how she, under strict instructions, actively encouraged young unmarried mothers to give away their babies to married couples whom society deemed to be more suitable parents in the 1970s.

The former social worker, who chose to hide behind the alias "Jan," said: "Basically my job was to shut them up, stop them (from) crying, get them to realise that giving up their baby was the best thing that they could do and get on with it."

Jan, who said she knew she had an awful job, was a trainee social worker at Sydney's Royal Hospital for Women when it was run by the Benevolent Society in 1972, ABC reported.

Although official figures are not available, ABC reported there was about a quarter of a million women who gave their children up for adoption in Australia between the 1920s and 1980s.

Margaret Freeman spoke to ABC News and said she gave birth at Newcastle's Mater Hospital in 1975 when she was 17. Her son was taken away instantly and was adopted right away.

"It wasn't like giving birth, it was just like an instant loss. You know for months beforehand you feel him moving and kicking and then he's not there, and not in your arms he's just gone," she said.

The federal senate has agreed to an inquiry into the practice of forcible adoption in Australia between the 1940s and 1980s, in support of a motion by Greens Senator Rachel Siewert on Nov 15.

"There is no doubt that many women were treated very badly as a result of (forced adoption) policies. Young and vulnerable mothers were pressured into adoptions, and often had to surrender their newborn children without being allowed to see them.

The senator stressed that the forced adoption policies will be felt by mothers who were unwilling to give their babies up for the rest of their lives, and the government must address the issue.