Five of the 35 marble graves commemorating World War II Diggers have been pulled from the ground and smashed.

Local veteran Rick Meehan, who along with his 33-year-old son Luke maintain the war graves for the Commonwealth War Graves, has been left shattered and dumbfounded by the blatant vandalism.

Mr Meehan said they cleaned the area last Tuesday and believe the vandalism may have happened over the weekend.

A visibly upset Mr Meehan said he was left "shaking" when he initially saw the damage.

"This is just shattering," said Mr Meehan.

"When I got up here I couldn't believe it. I can't understand why someone would want to do this.

"I've been looking after this area for about five years, looking after these Diggers who stay here and why someone would want to vandalise it, destroy what they [the veterans] have done for their country is beyond me.

"I'm shattered. I can't get over why this has been done."

It isn't the first time the Nowra War Cemetery has been vandalised, in 2016 nine graves at the cemetery had swastikas drawn on them.

Shoalhaven Council's director of assets and works Paul Keech was deeply dismayed at the news of the destruction.

"Such senseless destruction and disrespect is a sad reflection on the values of those who have committed these acts," Mr Keech said.

"This act is devastating for the families of the servicemen, the members of the RSL Sub-Branch who care for the area and the Nowra community in general."

The bereavement services unit of Shoalhaven Council is working with the Office of Australian War Graves to assist in assessing and repairing the damage.

Nowra police are appealing for witnesses, after the crime was reported to South Coast Police District on Monday, September 16.

Police said between sometime between Wednesday, September 11 and Monday, September 16 the five headstones within the military section of Nowra Cemetery were destroyed.

Police are appealing for anyone who may have seen anyone suspicious in or around the cemetery to contact Nowra Police Station on 4421 9699 or Crime Stoppers on 1800 333 000.

Police inquiries are continuing.