Hayden Raymond Ebejer, 20, sent explicit images and videos of himself to the fake Facebook profile and repeatedly tried to persuade the underage teen he believed was on the other end of the conversation to meet up with him for sex.

Ebejer was arrested in early January last year and immediately confessed to his crimes in an interview with police, telling them he'd "said some things [to her] he shouldn't have".

He told police he was "very lonely" at the time and had gotten "desperate" but also claimed he had wanted to start a relationship with the girl and not just use her for sex.

Ebejer pleaded guilty to six charges in Wollongong Local court on Thursday including three counts of using a carriage service to send indecent material to a person he believed was under 16 and one count of using a carriage service to procure a person he believed was under 16 for sexual activity.

In a set of agreed facts tendered to the court, police said they began speaking with Ebejer online after he accepted a friend request from the fake Facebook profile of a 14-year-old girl in November 2018.

The conversations turned sexual almost immediately, with Ebejer sending the girl an image of a list of questions and asking her if she wanted to "play".

The questions ranged from harmless queries about age and favourite television show to overtly sexual, including "what's your darkest secret", "what kind of underwear do you have on", "what's your bra/dick size" and "what's your favourite sexual position".

The pair began choosing and answering questions and when asked for his "darkest secret", Ebejer replied "I like girls younger then (sic) me".

"Like me? Lol," the undercover detective responded.

"Yeah," Ebejer replied, before sending through a picture of himself holding his erect penis.

The pair continued their Facebook conversation the next day and Ebejer's questions again turned deeply personal and sexual, culminating in him suggesting they go on a date at the weekend.

He then sent her another picture of his penis, this time asking if she wanted him to "do anything with it".

In several conversations over the following weeks, Ebejer revealed he'd thought about the teen while he masturbated; told her they could "touch each other's private parts" while on a date; said he was "horny"; that he was looking at pornography online; and that he wanted to touch her "virgina" (sic).

At one stage he also activated his web cam so she could watch him masturbate, while on another occasion he sent a video of a female masturbating and asked the teen to do the same thing to herself while wearing her school uniform.

Ebejer was repeatedly reminded of the girl's age during each of the conversations as the detective pretended to be the sexually inexperienced teen.

"I've never done it (sex) before," the officer wrote using her undercover persona.

Ebejer replied "it's okay, we can go slow".

Meanwhile, police seized Ebejer's electronic devices when he was arrested and subsequently discovered they contained hundreds of videos and images of child pornography.

The matter will return to court next month for a sentencing date to be set. Ebejer remains on bail.