Police contact Cabinet secretary Phil Gaetjens about Brittany Higgins

Following top cop fears, the PM's office halted its investigation into Brittany Higgins' rape claims.

Following complaints from the Australian Federal Police, an investigation into who in the prime minister's office knew about the alleged rape of former Liberal staffer Brittany Higgins in 2019 has been put on hold.

It comes after Australia's top cop voiced his fears to the country's top public servant about concurrent inquiries into the alleged rape.

Commissioner of the Australian Federal Police Reece Kershaw announced on Monday that he had contacted Department of Prime Minister and Cabinet Secretary Phil Gaetjens about the Brittany Higgins situation.

Gaetjens later reported that, after receiving Kershaw's advice, he put the internal investigation on hold on March 9.

Phil Gaetjens about Brittany Higgins
After AFP Commissioner Reece Kershaw (right) raised questions, an investigation into who in Prime Minister Scott Morrison's office knew about Brittany Higgins' (left) rape accusation was put on hold.

Gaetjens has been charged by Scott Morrison with determining who in the prime minister's office was aware of the accusation and when.

Kershaw said that he had talked to those involved in the alleged sexual harassment case about the necessity of allowing the criminal investigation to proceed.

He told a Senate estimates hearing in Canberra, "I also spoke with Mr Gaetjens, secretary of the department of prime minister and cabinet, that I'm especially worried about the intersection of his inquiry with our investigation."

Higgins believes she was assaulted inside Parliament House by a former colleague in March 2019.

The AFP commissioner wrote to Gaetjens on February 22 asking for the scope of his investigation's terms of reference, and later received that information.

Following Morrison's request for advice, Kershaw sent a letter to all MPs and senators about reporting crimes two days later.

Kershaw said Higgins' accusation was significant and was being investigated by the AFP's ACT policing arm.

“I will be constrained on what I will reveal in order to protect the ongoing criminal investigation,” he said.

“It is being handled with the utmost care and consideration, as well as supervision from our sensitive investigations oversight board.”

Kershaw also addressed past harassment charges leveled against Attorney-General Christian Porter, which he categorically rejects.

In February, he said, the AFP contacted NSW counterparts about the matter and issued all relevant documents.

In the meantime, a separate committee hearing has been postponed due to Senate President Scott Ryan's refusal to answer questions regarding the Higgins incident.

Ryan claimed that he would not comment on the charges, which are still under investigation by the police.

Phil Gaetjens about Brittany Higgins
Phil Gaetjens, Secretary of the Department of the Prime Minister and Cabinet (PMC).

Senators from the Labor Party were shocked by his response, which caused a 15-minute break in the proceedings.

Ryan also hinted that he would not respond to questions regarding Porter's claims due to the prospect of a coronial inquest into the woman's death.

Kimberley Kitching, a Labor senator, said it appeared to be a cover-up.

Penny Wong, the leader of the opposition in the upper house, asked Ryan about whether he and the prime minister discussed the hearing's "tactical approach."

Senator Ryan said, "I did not have any discussions about strategies or anything else."