Plymouth City Council has set up an independent inquiry over administrative problems in the lead-up to the general election in early June.
The investigation was launched after issues emerged with the sending out of postal vote packs to people who had applied for them.
According to the Guardian, a loss of 1,500 postal voting packs was due to a computer problem.
The council had already experienced issues regarding votes as the final number of votes declared for the Plymouth Sutton and Devonport constituency was incorrect, leaving 6,587 votes for Efford and Lipson out.