Royal Mail says Banbury postal votes will be delivered in time and posties will prioritise the special envelopes.
The assurance comes after many months of complaints about delays in deliveries with some people saying they had not received mail for two weeks or more.
Royal Mail said this week voters should send their postal voting pack back as soon as they can, the earlier the better, to make sure it is counted.
“Postal votes are designed to be readily identifiable when they enter our network, whether that’s a returned postal vote or an outgoing postal ballot pack,” said spokesman Jordan Bluer.“We play a pivotal role in the democratic process. The timely delivery of postal votes is an important task; it is one we are very proud to fulfil and one we are well prepared for.
“As part of our preparedness, we have a specialist elections team that handles every aspect of the elections programme, and we have the staff and expertise in place to manage the additional demand.
“Posties are briefed on what (the postal voting envelopes) look like and the urgency with which they need to be delivered.
"When they enter our network, whether that’s a return vote or outgoing ballot pack, they will be identified and delivered swiftly and accurately. We have a specialist elections team that oversees this operation, tracks election material and liaises with management at local delivery offices to ensure this is the case.”
The spokesman said postal votes that come in prior to the deadline (no later than July 3) will be delivered with the same urgency.
"As an additional precaution, to ensure all votes are counted we’ll be conducting a final day sweep at all our delivery offices to ensure all postal votes remaining in our network are identified and returned to the relevant local authority before the close of polling stations,” said Mr Bluer.
Gov.UK says first class letters are delivered one day after they’re dispatched.