A visiting professor has dramatically severed ties with Murdoch University over concerns about the university's legal action against a whistleblower who spoke out about the recruitment of international students.

Key points: Professor Robert Cribb was an adjunct professor and the Sir Walter Murdoch Distinguished Visiting Scholar with Murdoch University

Professor Robert Cribb was an adjunct professor and the Sir Walter Murdoch Distinguished Visiting Scholar with Murdoch University Dr Gerd Schröder-Turk was one of three academics who spoke out on Four Corners about international student admission standards

Dr Gerd Schröder-Turk was one of three academics who spoke out on Four Corners about international student admission standards Murdoch University has filed a cross-claim lawsuit seeking damages for money lost since he spoke publicly

Professor Robert Cribb resigned with immediate effect from his position as an adjunct professor and the Sir Walter Murdoch Distinguished Visiting Scholar late on Wednesday night, stating he considers the legal action to be a "dangerous and uncollegial persecution of a principled academic colleague".

Murdoch University is counter-suing Associate Professor Gerd Schröder-Turk for costs and damages, claiming his appearance on Four Corners in May caused reputational damage and has led to a drop in the number of international students and loss of revenue in the order of millions of dollars.

Dr Schröder-Turk and two of his Murdoch colleagues told the Four Corners investigation they were concerned about academic integrity and the welfare of a group of international students who were failing courses in higher than normal numbers.

Professor Cribb wrote to Murdoch's vice-chancellor, Professor Eeva Leinonen, in an email, stating that he felt Murdoch's move to counter-sue was designed to silence other academics.

"In marshalling its formidable resources against an individual in a civil case such as this, the university has shown that it wishes to intimidate others who may be tempted to expose poor practice that the university itself has failed to deal with adequately and openly," Professor Cribb wrote.

Dr Gerd Schröder-Turk is being counter-sued by Murdoch University. ( ABC News: Hugh Sando )

"The freedom to raise matters of public concern is a precious right which is under attack from many directions.

"Universities, by virtue of their intellectual mandate, ought to be bastions defending the right of free speech and freedom of information.

"The persecution of Associate Professor Schröder-Turk in the name of the university's commercial interests is a betrayal of values that ought to be at the heart of the Murdoch University endeavour and I can no longer be part of an institution which engages in such behaviour."

Protestors at Murdoch University show support for Professor Gerd Schröder-Turk. ( ABC News: Hugh Sando )

The resignation is the latest in a tide of criticism of Murdoch University, including an open letter signed by more than 50 laureate professors and a public petition signed by more than 26,000 people, urging the university to drop the legal action.

On Thursday, dozens of students, staff and members of the National Tertiary Education Union (NTEU) held a protest on campus holding signs with the phrase #istandwithgerd.

Professor Cribb, who holds a full-time position at the Australian National University in the school of Asia Pacific Affairs, told the ABC he felt he had no choice but to resign from Murdoch University after hearing of the court action against Dr Shroder-Turk.

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"I believe that this is an attempt to not so much to extract compensation from him but an attempt to intimidate other people from potentially revealing other poor practice," he said.

As a scholar of Asian history, Professor Cribb said he was particularly concerned about the use of civil litigation.

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"We know that in other countries legal action is sometimes used very effectively as a means of intimidating whistleblowers and preventing people from revealing problems within the institution," he said.

Professor Cribb received a response from Murdoch's deputy vice-chancellor, David Morrison, on Thursday.

Dear Robert, It is with great regret that I accept your resignation as a Sir Walter Murdoch Distinguished Visiting Scholar and adjunct professor of Murdoch University. From a personal perspective, it is most unfortunate that some of the current media commentary has guided your decision. While we are unable to comment on legal matters, I invite you to appraise yourself of the facts surrounding the case so you can be personally reassured that Murdoch is, and will continue to be, a fine university committed to the fundamental principles of free speech.

Murdoch University told the ABC they would not provide further comments to what Professor Morrison has said.

Previously, the university has declined to comment, saying the matter is before the courts, but remarked on Thursday's student protest.

"At Murdoch University we encourage our students to have a voice to be able to express themselves on matters they feel strongly about," the university said.