New South Wales health clinics and hospitals will start weighing children as part of new anti-obesity measures.

NSW Health is asking all frontline health staff to conduct mandatory growth assessments for young patients.

These will involve weighing kids, and even discussing healthy lifestyles or making referrals for weight loss clinics where needed.

The measure is not designed to shame children, according to Professor Louise Baur, a paediatrician at the Westmead Children's Hospital.

“Part of this is talking about height and weight in a normal way that's respectful,” she told reporters.

“It's not about creating anxiety, it is about helping people and providing options for families if there are concerns.”

Professor Baur said parents were often unaware of their child’s weight problem.

“We tend to compare our children with the other children in the class in school, so if there are quite a number of children who are overweight it may be hard to pick up they have a weight problem,” she said.

NSW Health Minister Brad Hazzard says early intervention is vital.

“If you're overweight everything is worse — you're more likely to get diabetes, you're more likely to get a range of cancers, illness generally is more likely to come your way,” Mr Hazzard said.

‘If we can get that message through to our children and get them healthy when they're young they're more likely to stay healthy for life.”

Opposition health spokesman Walt Secord said it “seems like a thought bubble”.

“I'm actually a bit surprised by this, I wonder if it's actually been thought through, I wonder what a dentist, chiropractor or speech pathologist thinks of this plan. I think it's been made up on the hop,” he said.