Moves to help parents trace children put up for adoption decades ago have been welcomed by support groups.
Many of those who want contact are siblings of wartime children
Pam Hodgkins, chief executive of the National Organisation for Counselling Adoptees and Parents, or NORCAP, said it would give everyone equal rights.
People can currently try to contact birth relatives by placing their details with the Adoption Register or through adoption agencies themselves.
Groups like NORCAP and British Adoption and Fostering (BAAF) can also help.
However, the provision of support can vary from one local authority to another because it is discretionary.
Ms Hodgkins said under the new Adoption and Children Bill, everyone would be entitled to ask an adoption support agency to offer them an intermediary service.
"What this new law will do is to make sure everyone has an equal opportunity to access a good quality service," she said.
"Whether the person is actually found is the first question because some people literally do disappear off the face of the earth, but not very many.
"Of course the adopted person then needs to consent to the disclosure of any information - it is an informed consent that the adoptive person has to give.
"It will not be a case that birth relatives will be able to contact adopted people directly. They will be able to access a service."
Ms Hodgkins, who was herself adopted, said: "I had the benefit of finding my birth mother before she died and I have a very good relationship with my father and his son."
She believes personal experience makes her better able to understand the needs of people who come to NORCAP.
"I think it probably makes me very aware of how significant knowing one's genetic heritage is.
"The connections people can make to birth relatives are different yet valuable in the same way as one's adoptive family is extremely valuable."
Finding siblings will be one of the greatest benefits of the new laws, she said, particularly for older people.
"Recently we have been working with people who were separated at the end of the war and, in fact, some of them were not even born when the child that was adopted was placed for adoption.
"But they've learned of that person since and desperately want to reach out and say 'I'm your brother, I'm your sister'.
"It's particularly the women who parted with babies in the 40s, 50s, 60s, simply because they were unmarried when they gave birth to these children.
"I think it's hard in the early years of the 21st Century to appreciate just how vindictive society's attitude was to unmarried parents.
"You could almost think it was the Victorian era - but it wasn't, it was less than 30 years ago."
A spokeswoman for BAAF said bringing in the new Adoption Support Agencies (ASAS) to act as an intermediary service would mean adoption agencies could concentrate on finding families for children.
Local authorities and adoption agencies will still play a role in providing information requested through the ASA but will not fulfil the principal role.
"It's been carefully thought out because adoption agencies are overstretched and have a real burden at the moment," the spokeswoman said.
"The main focus of their work is to find adoptive families for children that need them, so it's right that they should be able to get on with that work."