Dentists are welcoming Helen Clark's call for free dental care for all New Zealanders.

Through Twitter, the former Prime Minister has asked Jacinda Ardern to consider making tooth-care accessible for everyone.

Dentist and public health advocate, Rob Beaglehole said the discussion is long overdue, and that Ms Clark's solution would help the people most at risk of poor dental health.

''Childhood poverty is the number one risk factor for tooth decay. We know the lower down the socio-economic ladder you go, the more holes you have and the fewer teeth you have.''

He said money is often the biggest barrier for people.

''The first thing that needs to be looked at is who are the people that aren't accessing dental care in New Zealand, and it's my understanding it's people on low incomes.''