A New South Wales policewoman took her own life after having an affair with a senior officer, an inquest has heard.

The married mother of two, who can only be known as Officer A, took her life on July 3, 2013.

At the time she was suffering from post-traumatic stress disorder (PTSD) and depression.

The affair with the senior officer, who was a long-standing friend of her husband, was only discovered during a coronial investigation into her death.

In findings released on Friday, Deputy State Coroner Hugh Dillon said she also had inappropriate relationships with two other senior officers who were her direct supervisors.

He also found there was a culture of "ribald banter" in the office where she worked.

The coroner said affairs were common in the police force and recommended major changes to the force's conflict of interest policy to include "ongoing intimate relationships".

"Affairs can be deleterious to the organisation," he said.

"In my view, the police force may need to consider its own culture to ensure that officers are not placed in positions of conflict, are not psychologically harmed and that professional relationships are properly maintained for the good of the organisation and the community more generally."

He warned the service could learn from numerous scandals in the Australian Defence Force.

"They should be a warning to police forces of the dangers of allowing professional standards to be set by the lowest common denominators in a unit".

The inquest heard that Officer A had attempted suicide once before, but the NSW police service did not investigate the incident. Mr Dillon said this failure to investigate was extraordinary and a "significant systems failure".

Police medical officer said officer did not have PTSD

Before she died, Officer A was sent to see a police medical officer (PMO) who concluded, after a one-hour consultation, that this previous suicide attempt was not genuine and that she did not have PTSD.

He recommended Officer A be transferred to another police station the next day.

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Mr Dillon found the medical officer's assessment of Officer A was "flawed" and recommended that in future PMOs consult with an officer's own treating doctors before making such decisions.

On July 3, 2013, the day she died, Officer A was summoned to a meeting to be told she was being transferred. Her husband, known as Officer F, was not invited to attend as a support person.

Officer A left the office in a distressed state and drove to a state forest, where she took her life.

Mr Dillon said while the plan to move her was well-intentioned, it was "not well thought through".

"It was almost inevitable that she would feel slighted, isolated and alienated if the decision to move her was taken," he said.

"That she would react angrily and emotionally was a racing certainty."

He said an obvious lesson to be learned from her death was that in such delicate situations, a support person should be present for the officer.

The coroner also found Officer A had been distressed about her salary being reduced by 25 per cent, without the required notice.

"The failure to give Officer A proper notice... was an oversight by NSW Police Force staff and an apology for this mistake was sent to Officer A by email," Mr Dillon said.

Officer's death left family 'grief-stricken'

He said Officer A's death was "unutterably sad".

"She left behind two beautiful children and a devoted husband who are grief-stricken not only by what happened to Officer A but by how her life fell apart," he said.

In a statement, the NSW Police Force said the coroner's recommendations would "certainly contribute to any improvements currently being considered".

"The NSW Police Force has made significant advances over many years now to minimise the psychological impact of policing duties on our officers, who frequently undertake stressful and difficult work," the statement said.

"NSW Police has been improving its practices and procedures, and where they can be further improved to mitigate against these impacts, they will be.

"NSW Police believes officers who suffer any type of injury should be provided with all the necessary support and encouragement to return them to their workplace. Those who cannot can exit with dignity."