Number of missing postal ballots in Plymouth rises
More postal ballots have been reported missing in Plymouth - after hundreds of voters complained theirs had not been received.
It is understood 1,510 postal voting packs are unaccounted for.
Earlier reports suggested the number of people who had applied for a postal vote and not received their packs was far lower, at 580.
Plymouth City Council, which blamed a computer problem, apologised and said it was urgently investigating.
Polls are open from 07:00 to 22:00 BST on Thursday, and postal ballots can be used at polling stations.
The council said it was authorised to issue replacement post voting packs until 17:00 BST on polling day.
However, a spokeswoman said emergency proxy votes for those living abroad were not permitted under the circumstances.
Three constituencies are affected: South West Devon, Plymouth Moor View, and Plymouth Sutton and Devonport.
Emily Dymond, who lives in Canada but can vote in Plymouth Sutton and Devonport, said she was "really frustrated" not to receive her postal vote or proxy form.
She said after applying on 10 May, nothing arrived from the council. She sent 10 follow-up emails but heard nothing back.
She eventually spoke to a council employee who told her nothing could be done.
Ms Dymond, 27, said: "I don't understand how they can get away with it. I want to know how they will put it right."
BBC South West political correspondent Martyn Oates said Plymouth Sutton and Devonport was "the most marginal seat" in the region, so the missing ballots could prove "quite significant" there.
Stuart Pilcher, agent for Conservative candidate Oliver Colvile in the seat, said: "It's very very worrying that this issue has come about, voting is a right for everyone."
Tudor Evans, leader of the Labour opposition group on the city council and supporter of candidate Luke Pollard called it an "omnishambles" and he was "beside himself with rage".
For a complete list of candidates for the seat, click here.
What to do if you're affected
People can still return their postal ballots but they must be received by 22:00 BST on Thursday. They also have the option of taking them to a polling station in one of the three affected constituencies. Polling booths have also been set up at Council House in Plymouth, the headquarters of the council. If anyone who applied for a postal vote has not received a pack they should contact the council.
Royal Mail special deliveries are being used to get packs to as many voters as possible within the three constituencies.
The council is also trying to get packs to people who live outside the area, but said Plymouth people living overseas and without a postal ballot will not be able to vote.
It said: "We are still investigating the cause of the problem, which appears to have been due to an IT issue. We will determine how this has happened to ensure it cannot happen again."
Analysis by Martyn Oates, Political Editor , BBC South West
It's clearly embarrassing for a major local authority to have to be running around at the eleventh hour to make sure more than 1500 voters living in three different constituencies are actually able to vote in a general election.
The bigger challenge now, though, is trying to get ballot papers to postal addresses outside the Plymouth constituencies. It sounds as if some people willing and entitled to cast a vote in Plymouth will now be unable to through no fault of their own.
A Royal Mail spokesman said: "We have a dedicated postman collecting postal votes from the council and delivering these packs as soon as we receive them.
"We will continue to deliver any packs handed to us today [Wednesday]."