A Hastings District Council (HDC) spokesperson said they don't have any idea why someone would take the plaque, but called its theft "very disappointing".
To the HDC's knowledge, this is an isolated event.
"There have been no other plaques removed in recent history, that we are aware of," the spokesperson said.
The council has asked the public for any information on the whereabouts of the plaque.
But found or not, their intention is to replace it, with the parks team waiting for a quote for a new Sri Chinmoy Peace Walk plaque.
Removal of a plaque is considered damage to a council park or facilities, and if the person responsible is identified, the repercussions for their actions will depend on the damage level.
The HDC is asking that if you know the whereabouts of this plaque, please contact the council on (06) 871 5000.