But try telling that to sufferers of the disease planning to rally outside the department's offices in North Sydney on Friday. They are calling for recognition of the disease, which they believe affects as many as 200,000 people across the country.

They say there should be more research, increased accredited testing processes and education for doctors to recognise, test and treat both early- and chronic-stage Lyme disease.

The protesters will include outdoor workers in national parks who have contracted the disease and are backed by the Public Service Association. The PSA's industrial officer, Geo Papas, said: "It is outrageous that our government health authorities have buried their collective heads in the sand over this issue.

''This is a public interest issue and I call on the NSW government to initiate a public inquiry into this disease with a view to recognising its existence, educating medical professionals in its detection and treatment so as to minimise the impact it has on the lives of workers and the general public.

"I would not like to be someone who contracts this disease in NSW in the course of their employment because of the changes to the workers' compensation legislation, as you would have to fund your own legal challenge on the basis of a disease that is not recognised by government health authorities."

The protest organiser, Danielle Ryan, a 29-year-old project manager, was bitten by a tick at Mona Vale in 2002 and has suffered symptoms for 10 years without diagnosis. In May last year, she was finally diagnosed with chronic neurological-stage Lyme disease. She said: ''The chronic pain I have suffered from later stage Lyme disease was the most horrible time of my life, especially being unable to walk at one stage at the age of 28 without explanation. Most doctors treated me like I was some kind of psychotic crazy woman wanting attention. My family and I have been through hell and back over this.

''I had one of the leading infectious disease specialists in Sydney tell me, 'You can't have Lyme. It's not here.' I'm now trying to sell my house to move to the UK for a few months for treatment where they actually recognise Lyme disease and want to help patients get better.''

The director of health protection in NSW, Jeremy McAnulty, said an expert panel convened last year found there was no conclusive evidence of locally acquired Lyme disease but that the disease would be monitored.

The Health Minister, Jillian Skinner, said in a statement to The Sun-Herald the department was staffed by ''recognised specialists in monitoring and evaluating potential public health risks and developing appropriate responses when necessary''. A team of experts dealing with the potential incidence of Lyme disease ''has my total support''.