Auckland children with severe and often extremely painful teeth problems are having to wait more than eight months for treatment - double what they should be.
Under Ministry of Health standards, all patients requiring specialist appointments should be seen within four months.
But Auckland's regional dental health service cannot meet the timeframe.
Dental Association president Bill O'Connor said children waiting for treatment were facing serious problems.
"An abscessed tooth, deep decay in one or more or many teeth, they could be in a lot of pain, they may have a lot of infection going on," Dr O'Connor said.
And the delays were making things worse.
"They can escalate from being just decay in their teeth, if you leave that for eight months the tooth could well become severely abscessed and the child can become quite ill and obviously that's a long time to put up with pain and suffering," Dr O'Connor said.
In many cases, children with such severe dental problems had to be placed under general anaesthetic to be treated.
A report to the Auckland and Waitematā District Health Boards said nearly 2500 children are on the waiting list for a specialist dental appointment or dental treatment under general anaesthetic.
Every month about 200 children are added to the list, but because operating theatres are full, only 140 children are receiving treatment under general anaesthetic.
Auckland's regional hospital dental service is managed by the Auckland District Health Board. In a statement it said it was struggling to treat children within four months of referral - and many with severe dental problems were waiting more than eight months.
"This is due to a number of reasons, including pressures resulting from high population growth in the Auckland region," the statement said.
"We are focused on improving wait times through approaches such as providing additional clinics during weekends, increasing clinical staffing numbers."
Dr O'Connor said this was not good enough.
"Obviously, these kids need treating so something needs to be done now to increase the capacity of the DHBs to deal with the immediate problem, but long term the solution is to stop the problem in the first place.
"That's where the community oral health service needs possibly a reviewed and perhaps maybe more funding but certainly more resources put into it to get to these kids before they get to this point."
A dental public health researcher from Otago University, Professor Murray Thompson, said there was no quick fix.
"Generally, as poverty increases, as stress on a particular communities, poor people and poor households increases, we find that this problem goes up and it takes a long time and a lot of effort to turn it around."
He is about to release a study that will show the situation has improved in recent years: The average wait time for dental treatment needing general anaesthetic in Auckland four years ago was 14 months.