NSW Rural Fire Service Mid North Coast duty officer Terry Kitching said unfortunately the service has no leads in relation to solving the cause of the fires and is relying on the public's assistance.

He said the service will accept any information or video footage in relation to the suspicious fires.

Fire and Rescue NSW Laurieton crew were alerted to the Laurieton fire, near Henry Kendall Reserve, just after midday on Thursday, May 23.

Earlier in the week the RFS NSW were called to help contain two suspicious fires burning at Diamond Head Road, Diamond Head at 1.30pm on Tuesday, May 21.

NSW Rural Fire Service (RFS) Mid North Coast district inspector Max Ryan labelled the actions of people who deliberately lit the fires as disappointing.

Mr Ryan said the crew was alerted to the Diamond Head fire by the NSW National Parks and Wildlife Service.

"Our firefighters have to leave work, their homes and families to attend these fires," he said.

Fire crews also responded to other suspicious fires in Lake Cathie and Bonny Hills last week.

The fires will be investigated by the police.

To report information or if you have seen any suspicious activity please contact Crime Stoppers on 1800 333 000.

Meanwhile, Forestry Corporation of NSW continues hazard reduction burns across the region this week.

People should consider their health while smoke from hazard reduction burning is affecting air quality across parts of the Mid North Coast.

Fine smoke particles are known to affect the human breathing system. The smaller or finer the particles, the deeper they go into the lungs.

These particles can cause a variety of health problems, such as itchy or burning eyes, throat irritation, runny nose and illnesses such as bronchitis, according to acting director of the North Coast Public Health Unit, Greg Bell.

The smoke particles can also aggravate existing lung conditions, such as chronic bronchitis, emphysema and asthma.

Smoke particle levels are likely to be higher outdoors than indoors, so people sensitive to fine particles should limit the time they spend outside.

"People with asthma and other lung conditions should not engage in vigorous exercise and, if possible, they should stay in air-conditioned premises where filtration systems can help to reduce smoke particles in the air," Mr Bell said.

"Symptoms can occur for several days after smoke is inhaled, so people with the chronic respiratory conditions need to be vigilant with their treatment programs.

"If you have asthma or a lung condition and you develop symptoms such as shortness of breath, coughing or wheezing, follow your Asthma or Chronic Obstructive Pulmonary Disease (COPD) Action Plan.

"If symptoms do not settle, seek medical advice. If you are on home oxygen treatment, continue as prescribed and if breathlessness worsens, contact your doctor."

Healthy adults may also feel the effects of fine particles that can irritate the lungs, so it's wise to reschedule or cut back on prolonged or strenuous outdoor activities when smoke levels are high.

Healthy adults generally find that symptoms will clear after the smoke disappears.

For more information visit the Fires Near Me website or download the app.