Former Prime Minister Scott Morrison is set to give evidence at Senator Linda Reynolds and Brittany Higgins’ high-profile defamation battle.

Senator Reynolds is suing Ms Higgins over a series of social media posts containing alleged mistruths that she believes damaged her reputation.

Mr Morrison is expected to step into the witness box in the Perth court on Tuesday to answer questions about what he was told by the senator about the alleged rape of Brittany Higgins and when.

It follows evidence from Senator Reynolds’s partner Robert Reid.

Mr Reid told the trial on Monday the “whole saga has had an immeasurable impact on Linda, on myself”.

“It has affected every part of our life,” he told the Western Australian Supreme Court.

“I hope that one day we can get that relationship back.”

Mr Reid said the senator and his love was based on travel, politics, humour, family and spending time at the senator’s Bali home.

That all changed in 2021 when Ms Higgins went public with accusations about the senator covering up her alleged rape in 2019.

It led to Senator Reynolds having a public breakdown and being diagnosed with serious cardiac issues, the trial has been told.

“It has changed our lives utterly,” he said.

He said the senator’s medical issues had impacted her ability to travel.

“Linda now will have to take blood pressure monitors … the medication she has to take,” he said.

Mr Reid said the couple’s relationship with his children from his first marriage was also impacted.

He said his daughter didn’t initially believe the senator’s version of events.

“When this first erupted, in 2021, I know who she believed and it wasn’t Linda to start with,” he said.

“There was reticence from my daughter to engage with Linda.”

Mr Reid also said Ms Higgins’ allegations and the political firestorm that followed also impacted the senator’s social life.

“Linda’s invitation list has shrunk. Just the other day, there was an event where the leader of the opposition had to ask somebody to represent him in a function,” he said.

“Now I know the people he asked, one of them accepted. I actually suggested Linda as an option and his office said ‘wish her well’.”

Senator Reynolds’ interaction with the public has also changed, Mr Reid told the court.

“It has affected how people come up to her, some to sneer, the great majority of people to say ‘well done, keep it going’,” he said.