Young children from parts of northern NSW without fluoridated water are being hospitalised for mass extractions of rotten teeth at nearly twice the rate of other children.

Dentists and paediatricians in Lismore and Ballina say tooth decay among young children is at Third-World levels.

The situation has prompted the Australian Dental Association to urge the federal government to use its influence to force councils swayed by ''fringe groups who peddle fear … and conspiracy theories'' to embrace water fluoridation.

In a statement intended to make water fluoridation an election issue, the association's federal president, Karin Alexander, said the government needed to make fluoridation of drinking water a condition of funding for all states and territories, particularly NSW and Queensland, or face a rising tide of child dental emergencies.

''Political parties [need] to have the guts to get into the debate, show some leadership and back the science and the experts to improve the dental health of all Australians.''