New research from the NSW Bureau of Crime Statistics and Research shows a decline in the proportion of young offenders formally diverted from the court system through a police-issued warning, caution or youth justice conference.
The NSW youth diversion rate fell from 51.3 per cent in 2022-23 to 46.8 per cent in 2023-24.
From 2022-23 to 2023-24, youth court actions increased 10 per cent while the number of cautions fell 10.5 per cent and formal warnings 7.3 per cent.
Bureau executive director Jackie Fitzgerald said the nature of the crimes being committed was a factor.
"There has been a shift to more serious offending," she said.
"There's a similar number of legal actions but they have tended to be for robbery, car theft and break-ins and those offences are less likely to be diverted because they are so serious."
Ms Fitzgerald said the number of less serious offences had also decreased.
"Fewer cannabis possessions, and fewer offensive behaviour and language - those are often diverted but not coming up as much," she said.
While the nature of the crimes has changed, Ms Fitzgerald said it was likely police attitudes had also shifted.
"It's possible that it's the characteristics of the young people or it could be a practice change or preference by police to move towards a more serious response," she said.
Overall, the crime statistics also found an increase in serious offending across the state, particularly in family and sexual violence.
In the last two years, domestic violence-related assaults increased by 28.3 per cent, rising in 12 of 13 regional locations and 14 of 15 Sydney locations
Sexual assault increased 107 per cent, rising in all 13 regional locations and all 15 Sydney locations.