In a break with tradition it will be the first time in around 30 years naval personnel won't march at the Greenwell Point dawn service.

It is understood an occupational health and safety issue is the reason, with personnel not allowed to march in the dark due to safety concerns.

One of the highlights of the dawn services at Greenwell Point is when current serving navy personnel join ex-Diggers in making the solemn 450 metre march from Greenwell Point's main street to Anzac Park overlooking the Shoalhaven River.

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Hundreds of people line the sides of the street for the moving experience as the naval personnel, often from HMAS Albatross, and the former Diggers, school children, other community and services groups emerge from the dark, occasionally lit as they pass under streets lights.

A defence spokesperson confirmed navy will participate in the dawn service, but personnel would not be marching - "Safety was a factor in the decision not to march".

Instead the personnel will be already formed up, waiting for the march to arrive.

Defence said HMAS Albatross was providing a guest speaker, catafalque party and flag bearers for the Greenwell Point Dawn Service.

"The instruction to HMAS Albatross personnel, while different to what may have occurred in the past, has been provided cognisant of procedures traditionally observed by service personnel attending dawn services, and the particular physical and environmental conditions expected at Greenwell Point on April 25, 2019," a defence spokesperson said.

"Local commanders are responsible to ensure that risks to members on duty are reduced as reasonably practicable for dawn services across Australia."