A police officer has been found guilty of stalking after terrorising his female neighbour in the Victorian Yarra Valley region for more than two years.

Andrew John Tanner, a Leading Senior Constable at Victoria Police, was found guilty of five charges including stalking and engaging in sexual activity.

The 45-year-old – who is also a husband and father – flashed his neighbor dozens of times in 2016. He would stand in his backyard, open his dressing gown and expose himself.

Andrew John Tanner outside court in Melbourne. (9News)

Tanner's disturbing behaviour prompted his neighbour to build a tall fence between their properties.

The victim, who doesn't want to be identified, told 9News she thought her neighbour was a "creep" and would often ask, "Why me?"

At first she was scared to report the matter because he was a police officer.

"I didn't think anyone would believe me. It was my word against his," she said.

In 2018, Taskforce Salus launched an investigation into Tanner's conduct, installing CCTV cameras at the victim's home.

"Once the CCTV went up and they caught him doing what he was doing, that was the proof in the pudding," the victim said.

Despite being found guilty, the father of three maintains his innocence, claiming he thought he had consent from the victim.

Magistrate Simon Zebrowski described Tanner as "narcissistic", with a "lack of remorse" and "lack of insight".

"At worst, the defence he ran is cynical. At best, he honestly believes it. It's problematic either way," the magistrate said.

The victim, who is also a mother, has since had to move out of the property.

She told the court the matter had caused her difficulties because their children attend the same school, saying she avoids enrolling her children at sporting clubs out of fear she would bump into Tanner.

The victim said, "It makes me really anxious, (sic. about) repercussions, but I know I've done the right thing. I stood up for what is right even though he was a police officer and we won."

Tanner was supported by his wife, brother and mother in court. The court heard he's been a police officer since 2006, landing his "dream job" as a highway patrol officer later in his career.