Some 108,803 children were deemed at risk of serious harm in the 12 month period ending September 2019, while just 31,733 were seen by case workers, according to figures released by the Department of Justice and Communities.

Statistics for the December 2019 quarter also reveal that in the month of September, 37.5 per cent of children at risk of severe harm re-reported abuse within 12 months of having their case closed.

The NSW government has set a target to reduce this figure by 5.2 percentage points by June 2021.

NSW Families, Communities and Disability Services Minister Gareth Ward said the numbers could always be better but the government would work hard to deliver better outcomes for vulnerable children across the state.

"The latest data shows that our child protection caseworkers are seeing more children reported at risk of significant harm than ever before," Mr Ward said in a statement to AAP on Tuesday.

The number of children seen by case workers represented a three per cent increase on the number of children seen during the previous quarter, and a 20 per cent increase compared with the same period in the previous year, he said.

NSW Premier Gladys Berejiklian said some of the quarterly figures had increased because more children were investigated in the past year.

"Whilst the percentage of children who need that support and care, who are getting reported keeps going up, the number of children we're also checking up on has increased in the last 12 months," Ms Berejiklian told reporters.

"I'm not suggesting that's enough, but it is an increase on the previous few.

"So actually more children are ensured of being safe in their environments but unfortunately the number of reports have gone up as well."

Ms Berejiklian said for the first time in the past two decades, the trend of the number of children in out-of-home care was declining.

"We have the highest rates or what we call permanency and adoption now in NSW, the other states are actually looking at us," she said.

Australian Associated Press