Local councils are responsible for sending postal ballot forms to voters but some have blamed Royal Mail for delays.
A Royal Mail spokesperson said: “We have no backlog of postal votes and, whilst we are not complacent, we remain confident that postal votes handed to us on time will be delivered prior to polling day.
“Where specific concerns have been raised, we have investigated and confirmed ballot packs are being delivered as soon as they arrive in our network.”
The spokesperson said Royal Mail would welcome a review of the postal vote timetable for future elections.
However, Mr Flynn told Breakfast: “I would probably argue with some of the Royal Mail’s sentiments because if there’s no backlog then where’s the postal votes for my constituents?”
He said the prime minister had been warned a July election could pose issues in Scotland, where lots of families would be heading on holiday after schools broke up for the summer.
“If their postal vote didn’t land in time then they’re now disenfranchised in this election,” he added.
Postal affairs minister Mr Hollinrake told the Telegraph, external: “We urge Royal Mail to do all they can to make sure that postal votes get to the right people at the right time, and time is completely of the essence now.
“There’s a resourcing issue. They have recruited extra people and I welcome that but they’ve got to make sure they’ve got the right number of people to deliver the mail at busy times like this.”
