Civil Libertiies Council of NSW president Stephen Blanks said the Ombudsman should write to applicants who have applied for partner visas and been rejected in the past four years on the basis that they may be entitled to have their case reviewed.

"The Ombudsman should identify all those applicants rejected on the basis of the secret list and let them know their rights," Mr Blanks said.

Fairfax Media revealed on Sunday the department had a secret blacklist of 30 lawyers and migration agents which it was using to risk assess applications.

Agents of Concern List A and List B name lawyers and migration agents around the country who have been deemed to be high risk or of concern, leading to a higher level of scrutiny of their applications for clients seeking partner visas.

Some of the lawyers and agents on the covert list  have been in business for decades and more than three quarters of them have never had any official sanction against them.

Documents obtained by Fairfax Media under freedom of information (FOI) laws have revealed immigration officers were supposed to use the list as part of a risk assessment of applications for partner visas and then destroy it. But copies have been unofficially released through different sources. The department has said the list was created in 2010.

A spokeswoman for Immigration Minister Scott Morrison has said the list was used to assess risk and allocate cases to officers according to levels of experience and had ‘‘no impact on the assessment of cases''.

‘‘It simply ensures the application is assessed by an officer at the right level and experience to provide the best outcome for the applicant without compromising integrity," she said.

However, FOI documents show the discovery had triggered a departmental audit of the safeguard profiles and the agent of interest comments on ICSE (the departmental system). It also prompted a written apology to one lawyer and the admission from the first assistant secretary Garry Fleming that the list was being used "without appropriate oversight and control".

Lawyers and migration agents have privately voiced concerns they were being targeted by the department for challenging decisions or speaking out on behalf of their clients.

Marianne Dickie, sub-dean of migration law at the Australian National University, has supported the call for an investigation.

Ms Dickie said that it is important the issues be cleared up.

"There will be doubt over the decision making in those cases," she said.