A police officer who assaulted an Aboriginal boy during a violent arrest which left the victim injured and bleeding on the ground has lost his appeal.

Ryan Barlow, 30, had his appeal for assault occasioning actual bodily harm rejected at the District Court on Friday by Judge Catsanos, after being found guilty in May last year.

Barlow has deployed a controversial leg sweep manoeuvre on the teenager, who suffered cuts, a chipped tooth, an injured mouth as well as pain to his right knee and shoulder, face, jaw, and neck.

In December, Barlow avoided prison time, but was convicted and sentenced to an 18-month community correction order with supervision as well as being required to undertake 125 hours of community service work.

On Friday, whilst the correction order remained, on appeal, Barlow's community service was reduced to 95 hours.

Video of the incident in 2020, filmed by the boy's friend, showed the victim - who can't be named - saying, "I'll crack you across the jaw, bro" from four metres away when Barlow and two other officers approached the boy and his friends in Surry Hills at around 5pm.

Barlow immediately moved towards the boy, telling him to turn around and place his hands behind his back. The boy replied, "What the f**k?" but complied.

Over the next six seconds, Barlow deployed the sweep manoeuvre to bring down the child, who never moved towards the officer. Whilst not strictly prohibited, the move is not taught by NSW police.

In the video, the boy is heard telling Barlow whilst he is on the ground that he "can't f***ing stand up" and then, "you didn't have to hurt me".

During his trial, magistrate Rami Attia disagreed with the defence's claim that the controversial leg sweep amounted to a reasonable use of force.

The court was told the teen was given just over three seconds to comply with Barlow's orders before being brought to the ground.

In his police interview, Barlow said he felt threatened by the boy, who he argued tried to kick him and his fellow officer.

However, Magistrate Attia said these claims were "simply not accurate," pointing to video footage of the incident, and contended the use of force by Barlow was disproportionate.

Before his appeal, Barlow was still employed by NSW Police—17 months after being found guilty.

National Indigenous Times has contacted NSW Police for an update on his employment status.

Human rights law firm, National Justice Project, represented the victim. On Friday, chief executive George Newhouse said they were happy to see justice for their client in the case of police brutality.

"The video evidence of this assault was truly shocking, and it is no surprise the appeal was dismissed," Mr Newhouse said.

"It is a real shame that the trauma our young client suffered has been compounded by the officer's actions since in dragging this out through the courts".

The NSW Police have been heavily criticised for actions believed to target First Nations groups and communities.

This includes data revealing Aboriginal children are more likely to be strip searched, and communities with large Indigenous populations more likely to be monitored and fined during the COVID-19 lockdowns, pushing already disadvantaged families into financial hardship

The Law Enforcement Conduct Commission (LECC) have also been critical, highlighting incidents of coercing Indigenous children as young as ten to participate in interviews against legal advice, and police not wearing body-worn video (BWV).

Last year, police commissioner Karen Webb told the LECC that making NSW police officers responsible for addressing Closing the Gap targets would lead to "competing duties", described as an "outrageous statement" by human rights lawyers.

Premier Chris Minns has defended the force, who have cost the NSW taxpayer $160 million in civil claims over five years, and has said they are not to blame for the disproportionate Indigenous incarceration numbers in the state.