A northern New South Wales doctor says a seven-year-old child who is in a critical condition after being diagnosed with tetanus was not immunised.

The girl was initially treated at Lismore, before being transferred to Brisbane's Lady Cilento Children's Hospital on Wednesday.

Tetanus is a potentially fatal disease which is transmitted by bacteria in soil, and can enter the bloodstream through minor wounds.

Lismore paediatrician Chris Ingall, who treated the girl on Tuesday night, said cases of tetanus were rare in Australia.

"I have seen a number of cases of tetanus, mainly when I was working overseas," Dr Ingall said.

"Thankfully in Australia it's had very low rates of prevalence over the last few decades due to vaccination."

The North Coast region has some of the lowest vaccination rates in Australia.

There was controversy earlier this week when anti-vaccination advocate David Wolfe gave a sold-out talk in Mullumbimby, where childhood immunisation rates are around 50 per cent.

Dr Ingall said the anti-vaccination movement was an ongoing source of frustration for many local health professionals.

"When these campaigners come up with their quasi theories they're ignoring the fact that tetanus is with us," he said.

"It's part of our environment and it's not going to go away just because they have a fancy theory.

"This is a reality of not vaccinating."

Dr Ingall said the disease was characterised by excruciating facial and muscle spasms.

"Once they've got it [patients] need to be ventilated and paralysed so that their body can live through it," he said.

"It's just awful, it's so unnecessary that any child should have to go through this.

"She's a lovely little girl, lovely mum, very caring lovely family but a different belief system."

Alison Gaylard, from the Northern Rivers Vaccination Supporters group, said the case was a tragic wake-up call.

"People need to be made aware that there are still children suffering from vaccine-preventable diseases, particularly in this area," she said.

"I feel that people put their blinkers on and ignore it, or the information isn't getting out there.

"People need to know that these diseases occur through lack of vaccination."