Royal Mail have confirmed that eight post boxes have been closed to the public after dog excrement was forced through the slots.
The Express earlier reported that a post box on Agbrigg Road, close to the junction with Oakenshaw Street, had been temporarily closed by the Wakefield Collections Team after dog excrement was posted through the slot.
A piece of wood has been used to block the slot and prevent letters being inserted.
In a letter attached to the post box, Wakefield Collections Team apologised for the closure but said that they felt it was “necessary to protect both our staff and the public.”
Royal Mail have now confirmed that a further seven post boxes have been closed for the same reason.
A Royal Mail spokeswoman said: “We can confirm that eight postboxes around Agbrigg Road are currently out of service due to a member of the public posting dog excrement into the boxes.
“This has been an ongoing issue and is one we take extremely seriously, as it creates an unsafe and unpleasant working environment for our people who empty these boxes and for mail that is inside the boxes.
“The postboxes will remain closed as we continue to monitor the situation and the police investigate further.
“Any customers with concerns about their mail should contact Royal Mail Customer Services via royalmail.com, on Twitter @RoyalMailHelp, or by calling 03457 740 740.”
A spokesperson for West Yorkshire Police confirmed that enquiries into the damage were ongoing.
Anyone with any information on the incident is asked to contact West Yorkshire Police on 101, quoting reference 13180505399.
Information can also be given anonymously by calling CrimeStoppers on 0800 555 111.