Bargo resident Tyrell Edwards, 18, appeared at Picton Local Court via video link on Thursday, following his arrest the previous day.

He is charged with five counts of dangerous driving occasioning death in relation to Tuesday night's horror crash on a quiet rural road in the Wollondilly Shire village.

Documents tendered to the court said police had established the events leading up to the crash from CCTV footage, witness statements, scene examination and the police interview with Edwards.

Police alleged that at 7.53pm on Tuesday, September 6 the Nissan Navara ute driven by Edwards was travelling at high speeds north along East Parade at Buxton, which has a signposted limit of 60 km/h.

The vehicle allegedly crossed onto the wrong side of the road and the driver's side wheels hit the grassed shoulder of the roadway, before the vehicle returned to the correct side of the road.

Then about 40 metres north, police said, the vehicle began to spin and continued to do so for about 53 metres, before crossing the southbound lanes and crashing heavily into a tree on the passenger side.

Police said this caused the vehicle to spin the other way and run into a second tree, this time hitting the driver's side.

As a result of the impact the rear of the cabin was torn open and the back seat was thrown from the vehicle.

Police said the four passengers in the back were found a short distance away.

The passenger in the front was trapped, but Edwards managed to get himself out.

Nearby residents rushed to the scene and called emergency services.

Paramedics attended and declared all five passengers - three girls and two boys, two aged 14, two aged 15, and one 16 - dead at the scene.

Witnesses allegedly overheard Edwards saying: "I f--ked up, I'm going to jail".

He was taken to Liverpool Hospital with head and back pain, but released the following day.

Police arrested him at his home in Bargo and in an interview, he said there was a steering fault - which he described as "shaking, going left to right" - that made him unable to control the vehicle.

He also told police he tried to brake but the ute did not slow down much; however, police alleged his version of events was not consistent with evidence at the scene.

Edwards also told police he did not know how the fifth passenger came to be in his vehicle.

Police seized his phone and found a video he allegedly took while driving, a little over an hour before the crash.

They described it as showing Edwards purposefully and aggressively turning the steering wheel left to right, with two of the victims in the vehicle.

Police said the males could be heard laughing and one yelled: "We're going to spin out cuz".

Edwards' lawyer Karen Watson applied for his release on bail, but police opposed it.

Prosecutor Sergeant Sharron Garbutt said police held concerns that Edwards would commit serious offences and endanger the safety of the community.

Sergeant Garbutt told the court that Edwards had held a provisional licence since February 2021 and in that time had committed two speeding offences.

She said there were also concerns he would interfere with witnesses; given the small community, she said it was likely he would come into contact with witnesses.

Sergeant Garbutt told the court that it was a strong prosecution case, supported by footage of events leading up to the crash.

"The footage in particular supports the elements of the offence," she said, adding it "depicted a high level of moral culpability".

Ms Watson told the court Edwards lived at home with his parents, two younger brothers and cousins.

She said he came from a loving family and helped his mother care for the younger children.

Numerous friends and family members turned out at court to support Edwards, including his parents.

He worked as a labourer, Ms Watson said, and completed Year 11 in 2021.

She said Edwards needed psychological treatment for pre-existing anxiety and as a result of the crash, which had left him "significantly traumatised".

Ms Watson said he was willing to comply with any bail conditions, including a curfew or house arrest.

Magistrate Mark Douglass noted Edwards was a young man who had never been in custody before, with a stable job.

But what stood out, Magistrate Douglass said, was that Edwards had only held a licence for a short time but accumulated two speeding offences with two three-month periods of suspension, the most recent earlier this year.

"That's this year that this particular person has been sanctioned by Transport for NSW in relation to his manner of driving," he said.

Given the alleged "blatant breach" of the road rules, Magistrate Douglass said the court had no confidence Edwards would comply with bail conditions.

"He was suspended for two three-month periods in less than 18 months," he said.

"That was not enough, according to police, to stop what is a very serious course of dangerous driving."

Magistrate Douglass refused Edwards' release on bail, but ordered he receive mental health assessment and treatment in custody.

Edwards will return to court in November.