Doctors say waiting lists at Queensland's new paediatric allergy clinic are unlikely to fall until there are more specialists trained in the field.

When the Brisbane service opened earlier this month there was an 18-month wait for an appointment.

Now parents are being told it will take 21 months to get in.

There is only one fully-trained allergist working at the clinic, but Australian Medical Association spokesman Dr Ross Cartmill says he understands it is a long wait for parents.

"There's obviously a limit to what the allergist and the two trainee doctors can achieve," he said.

"They do have this extra support that's been added to put this clinic together, which is better than before, and it'll get better as we train more allergists."