"I would be overjoyed to get them back. This has made me feel very angry," Mrs O'Brien said.
She said her neighbour's security cameras captured the thieves and that footage had been passed to police.
Detective Sergeant John Wilson of Rotorua police said it was a very unusual series of thefts.
The thefts have occurred in the Pukehangi, Sunnybrook, Glenholme, Fenton Park and Ngongotaha areas. All were during the hours of darkness.
"It's reaching epidemic proportions, we have never seen anything like this before," Mr Wilson said.
Some of the items stolen have been of considerable size and weight, requiring at least two people to move them.
Among the items taken have been bird baths, statues, large planters and pots, water features, concrete balls, and outdoor furniture.
Due to the size and weight of the stolen property, police believe a light truck or van would have been used to transport them.
The stolen items were of a significant value cumulatively, as well as being of sentimental value to the owners, Mr Wilson said.
Mr Wilson said police were seeking the help of the public to identify those responsible and recover the items.
"They have been stolen from those who have taken some pride in wanting to beautify and personalise their properties.
"We would ask the public to be especially vigilant with any commercial type vehicles seen in residential areas at night which may seem out of place.
"Similarly, if you have recently been offered property such as this for sale, and you believe the circumstances are suspicious, then please contact the police."
Anyone with information is asked to contact the Rotorua police on (07) 348 0099. Information can also be provided anonymously to the organisation Crimestoppers on (0800) 555 111.