Oral evidence for the unfair dismissal case of Rob and Fern Messenger in Federal Court concluded on Thursday with two public servants employed with Ministerial and Parliamentary Services at the time the couple had their employment terminated in 2017.

Former MaPS state manager Andrew Witheford became involved in the matter when there was a dispute between Senator Lambie and her office manager, Mrs Messenger, in December 2016.

He told the court he was involved in initiating a mediation process between the pair, which Mrs Messenger declined to be involved in due to being on sick leave.

Senator Lambie had outlined a number of complaints against Mrs Messenger in a mediation document which Mr Witheford said he did not verify as it was not his role to do so.

"If there had been something that seemed patently ridiculous or untrue, then perhaps I would have queried it, but that was not the situation here," he said.

MaPS Victorian state manager Tori Rikys told the court she also did not verify claims against Senator Lambie as it was not her job to do so.

She became involved in the matter when a decision was made to draft a show-case letter three months later to Mr and Mrs Messenger.

She said Senator Lambie was left hurt and bewildered by the response she received.

Ms Rikys said the couple ridiculed her and it was obvious the working relationship between the senator and the two employees had completely broken down.

"The content was inappropriate and demonstrated a lack of trust between employer and employee," she said.

"We were providing the Messengers with the opportunity to respond [to complaints] and put their views forward, but all we got back was ridiculing of Senator Lambie."

In addition, Ms Rikys said they were surprised the response had been sent to former prime minister Malcolm Turnbull.

It was upon receipt of this letter that a process started to terminate employment, she said.

Mrs Messenger said they were entitled to share the correspondence with the Prime Minister as they were parliamentary staff members, and as such, that did not constitute serious misconduct.

Ms Rikys said the Prime Minister did not need to be involved in the relationship with a parliamentarian and their employees.

The case, before Justice John Snaden, was adjourned for a date to be set for oral submissions.