Heathcote MP Lee Evans yesterday called for calm while health experts investigate the possibility of a cancer cluster in Helensburgh.
"The main thing is, the most important thing is that we don't scare the horses," Mr Lee said.
"We need to keep level heads ... [so] that we don't panic the people of Helensburgh and make sure they're confident it's in hand and it's all under control," he said.
Nine-year-old Matthew Young became the sixth child in five years to be diagnosed with a blood cancer, prompting his mum Dianne to call for authorities to investigate.
NSW Health set up an expert panel bringing together epidemiological, public health, clinical and environmental specialists to consider evidence.
Other Helensburgh residents, who don't want to be named, have contacted the Mercury, praising Mrs Young for raising the issue.
Mr Lee said the Health Department investigated concerns about blood cancer cases in Helensburgh in 2008 and was "going back and looking at it again to make sure there isn't anything outside the norm in the community".
He said publicity was not helping the situation.
"The more you speak about it, the more it ends up being an issue, I'm concerned that there are some people within the community trying to whip up hysteria about it and it's important that we don't," Mr Lee said.
"The Health Department says yes obviously within the population it's an acceptable amount, although we'd like to see no cancer at all in our communities, but at this stage there isn't anything outside the norm."
Mr Lee said he understood Mrs Young's concerns but at this stage the re-examination of the 2008 investigation was precautionary.
"It's always terrible when your child has issues like this and looking for an answer is part of the process - I understand and we are there to support them in their path - but at this stage I've been told there's nothing outside the norm."
NSW Minister for Health Jillian Skinner said yesterday she was confident the expert panel would get to the bottom of the issue.
"I've certainly been kept informed of the advice from the public health officials down here in the Illawarra," she said.