Postboxes around Cowley and East Oxford are reportedly being temporarily sealed because collection times can not be met following the introduction of the LTN scheme.
A notice on one postbox informs residents that Royal Mail are not able to meet the final collection time "as a result of the LTN scheme".
It reads: "We are looking to resolve this as soon as possible by changing the final collection time."
"We do hope you will understand the reasons for this and hope that it will not cause you any inconvenience."
Cowley LTNs Twitter account captioned the picture: "Another own goal by OCC, these are popping up all over Cowley and East Oxford."