The plaques are being restored by local company Trophy Specialists to as near original condition as possible.
Health and safety / energy officer John Debney said that the graffiti attack was a sad and disrespectful act.
"We hope the restored plaques will reinforce the community's wider commitment to preserving the heritage of Palmerston North and honouring the contributions of those who gave up their lives for our freedom."
John Debney says two other plaques also require restoration and this will be carried out at a later date.
The restoration work is estimated to cost are around $3,000 and should be finished and ready to be reinstalled at the end of January 2013.