Bad news for tuck shops, good news for parents.

New survey data released shows that over the last 10 years, the number of students buying tuck shop lunches has halved.

That's a drop from 10 percent, to 5.

CensusAtSchool co-director Rachel Cunliffe says it's a positive trend for kids' health and parents' wallets.

"The cost of buying lunches is a big factor," Ms Cunliffe said.

"Another one is the overall awareness of bringing a healthy, packed lunch from home. I think a lot of parents are very aware of that."

Ms Cunliffe also believes that it could be down to fewer tuck shops carrying unhealthy food.

"A lot of the unhealthier options that kids were choosing to have are just not available now in schools."