"If they think it's a joke I'm not amused - it's my wife."
Mr Ah Kit said council should have told him about the maintenance before it was carried out, and wants a public apology.
"I paid for the plot, I paid for the headstone, it's my property and they shouldn't have touched it without my permission."
Council spokesman Sam Rossiter-Stead said when the land next to the grave collapsed the works were stopped immediately and the urn uplifted by the sexton.
The maintenance work was completed and the urn returned to the plot, and council staff decided formal written notification was appropriate and sent a letter immediately.
He said their intention was to return the headstone back to its original location, and if it was out of place council would work with Mr Ah Kit to resolve the situation.
"We would certainly like to apologise for any distress that has been caused. We carry out maintenance work in the cemetery on a daily basis and if there is any work planned which may involve graves being disturbed in any way, then we always contact those parties who may be affected.
"In this case it was an unexpected and unfortunate incident which was remedied quickly."
Chief executive Wes Ten Hove phoned Mr Ah Kit personally to apologise yesterday and the pair will meet later in the week to find a resolution.