Twenty-six street and business signs have been sawn-off over a two kilometre stretch of Parsons St in Springvale.
Now the Whanganui District Council is appealing to the public for information.
A Whanganui woman and her husband were driving to their business in Springvale on Monday when they realised that the Devon Rd sign was missing.
Sandra and Eddie Tofa soon discovered that not only was the street sign missing, but so was their River City Boxing Club business sign, as well as many others.
The signs stolen include street signs such as Grey St and Somerset Rd, as well as signs directing traffic to Kaierau Rugby Club and Springvale Garden Centre.
Sandra Tofa said the vandalism was frustrating for business owners who paid for their signs.
"When I saw ours was missing, I thought 'little s**ts,' somebody's taken it for their shed obviously," Tofa said.
"It's quite annoying, especially at night because it's dark around those areas so you're looking for the street signs to know you're down the right street."
The Tofas paid $80 to get their sign made up and put in place and if they want a new one they will have to pay again.
They had a resident call into their gym shared with Kaierau on Devon Rd on Tuesday, who told them they had turned down the wrong street due to the missing signs.
Meanwhile, the council is requesting that anyone with information about the stolen signs inform the police.
Council's senior roading engineer Brent Holmes said the stealing of signs was not generally a problem in Whanganui.
"The occasional sign gets stolen, usually for novelty value, [but] we can't recall such a large number of signs stolen at one time before," Holmes said.
"Twenty-six signs would take considerable time over that 2km length so it would be brazen to have done it by stealth on such a prominent route that has bright street lighting."
Holmes said the signs would have very little scrap metal value and it would be obvious if they were taken to a recycling yard for cash.
Despite this, replacement of all the signs would prove costly.
"Each sign, including combinations of post, fittings and labour installation costs between $300 and $500 to replace," Holmes said.
"Downer coordinates this work under the Whanganui Alliance road maintenance contract."
Anyone who has heard anything or seen a stockpile of blue signs should call police on 105.